CA2180799C - Test tube for determining the erythrocyte sedimentation rate and a surfactant for use therein - Google Patents
Test tube for determining the erythrocyte sedimentation rate and a surfactant for use therein Download PDFInfo
- Publication number
- CA2180799C CA2180799C CA002180799A CA2180799A CA2180799C CA 2180799 C CA2180799 C CA 2180799C CA 002180799 A CA002180799 A CA 002180799A CA 2180799 A CA2180799 A CA 2180799A CA 2180799 C CA2180799 C CA 2180799C
- Authority
- CA
- Canada
- Prior art keywords
- blood
- test tube
- tube
- surfactant
- column
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L3/00—Containers or dishes for laboratory use, e.g. laboratory glassware; Droppers
- B01L3/50—Containers for the purpose of retaining a material to be analysed, e.g. test tubes
- B01L3/508—Containers for the purpose of retaining a material to be analysed, e.g. test tubes rigid containers not provided for above
- B01L3/5082—Test tubes per se
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01L—CHEMICAL OR PHYSICAL LABORATORY APPARATUS FOR GENERAL USE
- B01L9/00—Supporting devices; Holding devices
- B01L9/06—Test-tube stands; Test-tube holders
Abstract
In an improved method for measuring the erythrocyte sedimentation rate (ESR) a pre-evacuated test tube (T) is used to collect a blood specimen. The tube (T) ismade of a material such as glass or plastics and contains an anticoagulant agent.
In order to facilitate mixing of the blood sample a surfactant such as an organo-silicone fluid is provided in the tube (T) as an additive.
In order to facilitate mixing of the blood sample a surfactant such as an organo-silicone fluid is provided in the tube (T) as an additive.
Description
A test tube for ~ .; "p the ~l y lL u~ r L~ ~G. ~ - rate amd a surfactant for use therein The present rnvention relates generally to d~ ~ the ~ rlL~u~.rk~ sedimen-tation rate (ESR) in a blood sample. The standard laboratory method heretofore used for measuring ESR is the so-called Westergren method. A general review of that method is provided in "ICSH ~ ~.. ~ .. I .. ~A I ' 1:~ for .~ of c~yll~u~"rl~ im~nt~ti/m rate" published in Journal of Clinical Pathology 1993;
46: 198-203.
Essentially, the Westergren method provides for a sample of blood to be collected in a test tube (pipette) to form a 200 mm blood column in the presence of an anti-coagulant. A~ter mi~cing the specimen briefiy, the test tube is loaded into a device or an ~lAL U~l~ including sensors such as an optical sensor to record the location of the blood/air meniscus at an initial time. A~er a period of 60 or 120 minutes, the operator or the sensor then identifies and measures the location of the cell/plasma interface. The distance in millimetres from initial blood/air meniscus and the final cell/rla~m~ int~rface gives the typical Westergren output value for the test which is e pressed in units of mm/hr.
A basic disadvantage of the cu., ~ iu~l~l Westergren method lies in the consider-able length of the test tube (typically in e2~cess of 200 mm) which makes it un-suitable for Ise in collecting blood directly. Consequently, blood for t;.e test has to be taken either by using a syringe or a pre-evacuated tube and the blood thus collected must then be lA~ to the Westergren test tube. In addition to being 1~nr~ti~1 guch a procedure expoges the operator to the danger of contacting the blood during the transfer process.
Systems dispensing with such a drawback and carrying out ESR ~ . . .; . . ,. t: - . us-rng tubes ~ l ly shorter than the standard 200 mm Westergren pipette are already available.
Exemplary of such prior art is, for instance, the ESR measuring system sold under the trademark SEDISCAN by the assignee of the present ~rFIir~t;rm A SEDI-SCAN illai.lUlU.,.~ is adapted for use in connection with tubes (sold under the trademark SEDITAINER - both SEDISCAN and SEDITAINER being registered Il ad~ al 1. h of Becton Dickinson and Company) essentially comprised of 6 ml draw tube of 120 mm length and 10.25 mm outer diameter containing liquid sodinm citrate/citric acid at 4:1 ratio. Using the above tube, the SEDISCAN ~ u~. .
provides an e~trapolated Westergren value after 30 minutes which compares well to actual 60 and 120 minutes Westergren values. However, it is necessary to e~amine nearly the entire tube length (about 70-80 mm of the blood column heightof 100 mm) in order to predict the ESR The tube is held verticalb.
Another system using "short" tubes is sold under the trade name VESMATIC by the Italian company Diesse Diagnostica Senese S.r.l.. The tube for use in this latter system has a rectangular shape overaL amd a triangular shape of the tube bottom.un, nearly the entire tube length must be scanned which leads to using an additional plastics outer sleeve to apply patient bar code or i~l~.,l.;l';. -1;~", labels.
The outer sleeve and the patient i~ntifi(~tl~ln data must be removed from the tube before this is placed in the instrument for carrying out the test. Cu~e~u~l-Lly, the-re is an actual danger that, due to the high number of tubes tested ~UU~.UUl~.lUy in a laboratory, a diagnostic result may be incorrectly assigned to the wrong patient due to a mistake in association of the clinical result for a tube with the patient irl~ntifi~t.i~m con~ined on the removed outer sleeve.
So, it is practically a mandatory I~U,Uil~ for any test tube for proper use m ESR measuring test to carry patient ;,1 ., I i l i. ~: . data which must not and cannot be removed at any time, while carrying out the test.
Also, there is a growing trend in the field of ESR ~ -- to provide reading ofthetestfinalvaluesina~,~,.,;l';~..-ll.lyshortertimethanthestandard60minutes of the Westergren method. Finally, the quantity of blood required for the test ~and ~ ~ ~ ` 21~8GZ799 y the qu~mtity of blood to be taken from the patient) is to be made as smail as possible.
The present imvention basical;Zy a,ims at providing a solution which joint,iy over-comes the drawbacks of the prior art solutions, i.e. by providimg an ESR determina-tion prooedure, where:
- ~short" tubes are used, preferably adapted for direct blood col;Zection;
- patient irl~ntifi~ data, once applied onto the tube, cannot be removed from it, thereby making it impossible to dis-associate the specimen from the patient - reiiable ESR values are provided in a term much shorter then the standard 60 or 120 minutes of the Westergren; and - the quantity of blood to be taken from the patient is min;mie~
A method and apparatus whicLZ permit reZiable ESR values to be provided in a short term (e.g. 20 minutes or less) Wil;Z be described in the following which constitute the subject matter of a European Patent appZication filed on an even date by the same Applicant of the present ~rrlil-~ti~n ~ -Specifica;Zly, the invention relates to a test tube ~ ",g an i~ over the prior art as i~Y~mr! fi^~l by the SEDITAINER~ test tube referred to in the fore-going .
Essentially, the underiying problem of the invention is providing an improved test tube by means of which the resuits obtained by the captioned new method and apparatus may be optimized. According to the present invention, that problem is solved by means of a test tube having the features set forth in the claims. The imvention a;Zso relates to a surfactant for use im such an improved test tube.
In the presently preferred ~ G-~ . of the invention, a ~ u~ed test tubeis used to collect ~e specimen which is made of such a material as glass or plastics and which contains an ~ v ~ The tube is then put into a rack and loaded mto an i~ llell~ which mixes the specimen briefly. The i~L ~ then uses optical sensors to record the location of the blood/air meniscu~ at an initial time.
At ~ time intervals thereafter for periods up to 30 minutes, typically 20 minutes or less, the optical sensors then identify and measure the location of the cell/plasma mterface. These measured values are then converted by a given ,,. T ,I e.g. am algorithm, to the values which would be obtained using the classical Westergren method (200 mm blood column height and blood to citrate ratio of 4:1).
When a small bore evacuated blood collection tube containing am a~ ,vp~ vlal 1 ~ is used several ~ , should be preferably satisfied in order for the tube to function in a most ~ali~ra~vly way. These requirements are as follows:
- the anticoagulant must be rapidly mi ~ed with the blood sample at the time of draw to insure a full anticoagulation effect;
- the tube must contain a thoroughly l~ "Pv l~ suspension of erythro-cytes prior to setting up the ESR test in order to obtain optimal results;
- the additive/anticoagulant mu~;t not interfere with the hslP~3tr parameters of blood In the invention, in order to sati~ly the first two ~ , a surfactant is added to the tube to promote rapid mi~cing of the contents by reducrng the surface tension of the blood sample to the glass tube. This allows for adequate anti-coagulation of the blood specimçn during draw. In addition, the amount of mi~ing(ie. agitation or stirring) required to insure a 1 . ~ suspension of erythro-cybs during ESR set up is reduced because the tube mi~es faster which in turn causes more turbulence within the tube thereby stirring the specimen.
Generallythereisan~l.. ,1;~1 l~la~lullaLubetweenmilbngtimeandconcentra-tion of surfactant, and at a~uulu~hlla~ely 1% by weight the fasbst mi~ing time was found to be achieved.
2 1 ~
A similar ~rrnr PntiAI lel.l~iu~L~ was fûund to êxiSt between mi~ing time and diameter ûf the glass tube. Due to the use ûf the surfact~mt a 6mm inside diameter, 8 mm ûutside diameter tube was found to mr almûst as fast as an 8 mm irside diameter 10 mm ûutside diameter tube withûut the use of the surfactant.
Briefly stated the key physical property that the surfactant must exhibit is thelowering of the surface tensiûn of whole blood to the glass tube. The surfactantmust alsû nût interfere with the 11A ~ y prûperties ûf human bloûd. Fûr elcample, the surfactant must not effect the alpha-globulin interaction with erythro-cytes as this is a key factor in erythrocyte ~.~.l;,,.~,.lUl .... rate testing (ESR).
The surfactant must alsû preferably be:
- irradiatiûn stable, thereby allûwing Cobalt 60 ~tPril;7AtiAn of the tube;
- chernically stable e.g in a buffered Tri-sodium citrate anticoag lIant;
ut,ld~ stable over the desired range of use, as well as during the transit ûf the product from the plant of the customer.
For e ample, somP ~ b were found to become irreversibly cloudy in the citrate anticoagulant when heated above 50C This is perceived as a fungal/bacte-rial growth in the tube, and is ~]nû-~Ppt~hlP
Desirably, the surfactant is a noniûnic surfactdnt. An example of such a surfactant isanor~An~A. ili~nP Preferably,theul~ il; r IPiS apolyalkyleneoxidemodified pûlydimethylsiloxane. Polyalkyleneor~ide modified p~ly~ llyl siloxanes are foundto be stable with irradnation, do not cause the blood to haemolysis and increases the rate of mixing ûf the blood sample.
':
In a thoroughly ull~ d manner, the solution of the invention was found to be suitable for satisfactory and reliable use also in a ~manual" ESR d~ iiu..
procedure, wherein the test tube is held vertically during the standard 60-120 minute period and reading is A. . . IIII;A~ IP~l simply be eye against a reference scale.
~ ` 2 ~ 80799 The invention will now be described, purely by way of er~ample, with reference to anne~ed drawmgs, wherein:
- figl shows a test tube according to the invention, - figs.2 and 3 show L.16~ lly the typical ~ul~6~ -1 of device of the invention, and - figæ.4 to 7 show the correlation between the results of the method of the invention and the results which would be obtained using the classical Westergrenmethod.
In fig. 1 an exemplary tube according to the invention is generally designated T.
Such a tube T - intended to define a cavity for forming a column of blood whose ESR is to be determined - has a tubular, preferably cylindrical wall with an outside diameter of not less than about 7 mm and not more than about 9 mm. The length of the tube T (roughly ~u~l~,UUl~Uillg to the height of the blood column formed therein which is preferably not less than about 75 mm, but not more than about 105 mm) is preferably about 80 mm. The inside diameter is preferably not less than about 5 mm and not more than about 7 mm and still preferably about 6 mm.
. .
IL L~Iue~ of the specific ~" .T .r,.~; . . .~" t, the inner diameter of the tube T must be ic;~Uy large to allow the blood specimen used for the test to mir adequately ;.,.",a.~ ly after co31ecting to ensure complete ~uti~,uz-6ulaLul- is achie~-cd. Sub-sequently, imrnrrTi~taly before initiating the me~ul~u~llt of the ESR, the speci-men must be uniformly and completely mr~ed to re-suspend ,blood cells.
The inner diameter and tube length should also be sufficiently small to minimisethe volume of the blood required from the patient for the test, since excessive blood lost by patients is considered rl~ :., ;, . . . I ~l to their health. This is particularly the case for paediatric patients who have small blood volumes amd geriatric patientswho have diminished capacity to regenerate blood cells. In the ~,U~UUdtiUIl described, blood I ~U Uil ~ i would be typically less than 2 mls which is cûnsider-ed ~ulTi~,icuUy small to have little impact on patient health.
The outer diameter and tube wall thickness must be sufficiently large to add sufficient strength and rigidity to ensure the tube does not break or bend during hamdling and ~ . testing. However, they should be ~ .ie~l~ly small to ensure the tube is easy to cut, form and glaze as in the case of a glass tube orinjection mouldea as m the case of a plastics tube. Excess material leads to higher m~n~ t--r~n~ cost and an overly thick tube wall could reduce the ability of an optical viewing device to see through the wall when attempting to identifying the meniscus amd the interface.
Optical imagmg devices, such as a LCDs, linear CCDs and video cameras, are pre-ferably used in connection with a visibly ~ tube wall (at least insofar as the "wmdow" of the tube actually observed is concerned), e.g. made of glass or plastics Alternative ~ ltq can however be envisaged~ wherein non-optical/sensors and/or visibly opaque, non-transparent tube walls are used.
E~emp~aryofsuchalternative~mhqrlimPnt~areimagingdevicesoperatingoutside the visible range (e.g infrared radiation) or devices operating with other kinds of radiation or based on other physical rh~n~;n~n~ (e g. capacitive sensors and thelike) Optical devices are however preferred due to the current availability of devicesadapted for use within the framework of the invention. E~cemplary of such devices are, in addition to the one used in the assignee's SEDISCANR system, those sold under the trade names Sony CCB-~q25/CE (CCD) and Sony PSB9151A (~w~r board) [Sony, Kanafawa, Japan] and Computak 6mm 1:1-2 1/2" C (Lens from Japan).
The open end of the tube T is preferably sealed by a stopper S having vacuum andmoisture barrier prqperties suitable to maintain the additive contents and blooddrawing capability for periods in el~cess of two weeks and preferably for periods in excess of one year.
The tube T according to the invention may be packaged and sold as a stand-alone,disposable, product comprised of the tube body proper (made of glass or plastics, for instance) pre-evacuated and sealed by the stopper S and also including a quantity of additive A Primarily, the additive is intended to act as an anti-~ tin~ agent/mixing aid.
Preferably, the additive is a mixture of triffodium citrate (Na3) and citric acid mixed in an aqueous solution to achieve a molarity of 0.105 M-0.135 M. Sufficient solution (e.g. 0.46 cc - referring to the preferred dimensions of the tube T referred to in the foregoing) is dispensed into the tube T during ."~".,r,.. ~... ;..g in order to ensure a blood to additive ratio upon specimen collection of 4:L However, when using liquid citrate solutions, blood to additive ratio starting at about 2:1 and below and up to about 10:1 and above are possible; the m~th-~m~ti(~l algorithm which converts the observed rate of cell settling to the claffsical Westergren value is adapted accordingly. Likewise, alternative anticoagulants such as EDTA Hiru-din and its analogues or potassium and sodium oxalate can be used in a variety of forms, such as liquid, freeze dried, powder or spray coatings. Each may be equally effective in anticoagulating the specimen without haemolysis and with an appro-priate ".~ 1 algorithm will allow conversion of the observed value to the Westergren value. Non-liquid, e.g. dry additives are usually preferred in the case of plastics tubes due to the well-known tendency of plastic tube to lose moisture.
Aso, to further enhance and facilitate mixing of the specimen in the tube irrespect-ive of the ~im~nqionq thereof, a component which reduces the surface tension of the blood is added to the tube as a coating or combined with the anticoagulant in its liquid or dry form. Desirably, the surfactant is a nonionic surfactant. An example of such a surfactant is an or~n~ilirnn~ Preferably, the or~n~-sili~ n-~ is a polyalkylenoxide modified polydimethyl-giloxane. Polyalkyleneoxide modified poly-dimethyl siloxanes are found to be stable with irradiation, do not cause the blood haemolysis and increases the rate of mixing the specimen to provide a well anticoa-gulated amd hulllu~ eou~ gpecimen without celi ~A~aliu.l or clotting.
2 ~ 80799 The fastest r~i~ing time was found to be achieved at ~ J,UI u~ aluly 1% cûncelltra-tion by weight.
Fig2 and 3 show a rack l adapted for receiving o.ne or, preferably, a plurality of tubes T, a light source 2, such as a 11 uu, ~c~, light arranged on one side of the rack l to create b~lu~d i1111minqti~m, as well as am optical ~naging device suchas a video camera 3, arranged on the other side of the rack l and adapted for viewing, as better described in the following, the tube or the tubes T against the background illllminqti~n created by the 30urce 2.
The location of the cell/plasma interface (c~-hGmqtirqlly designated I in fig.2~ is thus detected as a contragted image (dark/clear, black~white) against said background ilT~lminqti~n In the preferred l~mhofTim~nt shown in fig.2, the rack I is essentially comprised of a C-shaped frame having opposite lower 4 and upper 5 arIns adapted for securely receiving the lower and upper ends of the tube or tubes T. The two horizontal arms 4, 5 are connected by an upright arm 6 which is rigidly fi~ed to one of the arms (for instance upper arm 5) and is hinged at 7 to the other (in the present instance low-er) arm 4. Tbis ~ 1 ~u~ i permits the rack l to be opened to insert the or each tuT~e ~ into respectivc cavities ~ provided in the lower arm 4 and then securelylocked to their final position for carrying out the test by bringing the rack l to its closed pOsitioff wit~. the upp~r arm 5 (having respective cavities or a cutout on the lower side thereof - not visible in the drawing) to engage the upper ends of the tube or tubes T (cTosed by the stopper S). The racl~ I is then locked to its closed position by means of a lock m~r~qnicm controlled by a thumb-actuated slider 9.
,~
According to an dl 1 ~14~ well-known per se, the camera 3 has associated there-with drive means (6uch as a motor-driven toothed belt 3a) which cause it to under-go a traYerse movement (as shûwn by the double-pointed arrow of fig. 3) along the tube or tubes T. The motor moves the camera to view each rack (three such racks `~ 2~80799 Are provided in a linear array in the currently preferred ~.~\ho.l;.. ,.-,.t of the inven-tion). The motor does not move the camera during the period when the camera is viewing a specific rack. The cAmera sees a 2~im-~nC;~nA~ picture of the rack andthus can see the entire aspect of each tube in a rack After reading one rack thecAmera is moved by the motor to view the ne~t rack Also, associated with the rack 1 is a rotary mounting fi~ture including a rotAry platform or drum D carrying supporting formations which enable the rack 1 to be safely retained on the mount-ing fi~ture as this is rotated about a horizontal a~is ~ under the action of motor means (not shown). Thus, the rack 1 and the tube or tubes T located therein to be vertically rotated about an axis ~ to achieve thorough miring of the specimen im n..iiAtPIy before initiating the optical reading The rack 1 also allows the tube or tubes T to be optically observed from the side st-Arting ;, - ~ y above the blood/ air meniscus and continuing downward over a distance defining a window W as e~plained irl detail in the following Even though preferred at present, the rack, . I ~,~t,, . ~ described in the foregoing is not - per se - critical to the invention. Other ~.,.,.~;. .,~ .1.~ such as the one current~y used in the SEDISCAN~ system, can be used. I~nis also applies to the nature of the imagmg device embodied by the video camera 3. As an alternative toLCDs, linear CCD arrays and other devices (including non-optical devices) may beused.
Also, the arrangement for causing the camera 3 to move along the rack array, as well as the rotary mounting fir~ture for the racks 1, are ~ v~ al in the art anddo not require to be described in further detAil.
The foregoing also applies - in general terms - to the computer~conhrolled arrange-ment adopted for processing the output signal from the camera 3 and the possi-bility of usmg a mamual scanner 10 for identify-ing each and every tube T as it is loaded into the respective rack 1. The manual scanner 10 enables each patient's nhfirAt.~n data (usually in the form of a bar code) to be read from a label L
2l80799 apphed around the lower portion of eaeh tube T when collecting the blood samples.
Both the output signal (which is usually eonverted to a digital format) as well the signal from the manual seanner 10 are fed to a data processing unit, such as a personal eomputer 11. As an alternative to a y~ general purpose eomputers, a dedieated eomputer or proeessor ean be used. Suitable y~ o~ g (aceording to well-known eriteria whieh are not required to be deseribed here) enables each tube T to be safely identified as sueh, prior to loading into the instrument, while the respective camera reading 3, converted to a standard Wester-gren value, ean be outputted as a visual display on a sereen and/or a hard eopy printout or ~ P~ electronically to the host computer managing patient data in the laboratory. For a general review of the general prineiples of operation of sueh a proeessing unit, reference may be made to the User's Guide to the SEDIS~ software available with Becton Dickinson Vacutainer Systems and Cell Seience Product Europe for use with the SED~SCANR measuring system. Further details concerning the algorithm adopted for converting the camera reading 3 to standard of Westergren values are provided in the following.
When a plurality of tubes (such as fifteen tubes) T are tested simultaneously in a raek, these are preferably arranged in the rack in an array including two parallel rows, as shown in fig.2, with the tubes T in the adjacent rows suitably staggered or offset in order to make sure that all the tubes T in the two-row array can be ins-pected by the camera 3 moving along a line parallel to the two rows Preferably, the locations of the tubes in each rack 1 are such that all the tubes in the raek can be inspected ~im~ nPo~ y by the camera 3 positioned at a given pomt with respect of the rack 1. That point is preferably chosen to eorrespond to a central positioning of the camera 3 with respect to the length of the raek.
As the tubes in each rack 1 can be viewed .cirn~ nP-mcly by the camera 3 from a single location, the camera 3 needs to be stopped only once for eaeh rack, without any scanning movement being required. In the presently preferred ~ I,odi~ of `-- ` 21 80799 the invention7 three racks are arranged to be tested hi~ v~ y~ and the movement of the camera 3 along the guide 3a is thus stopped three times. Suitable controls may however be provided in order to prevent the camera from stopping atamy location where, for any reasons, no rack, a rack containmg no tubes or a rack containing only empty tubes are arramged.
From fig.3 it will be dl)lVl~d~td that, in the preferred ~ vl;~ of the invention, the tubes T are held inclined at an angle o with respect to the vertical.
As the classic Westergren method specifies that the specimen be e~amined after remaining vertically upright for 60 or 120 minutes, the cliniciam or laboratorian must wait this long before providing a diagnostic result for the patient. This mevitably results in in~t'li~iPn~ and high costs in the health care ~., vi- Vlllll~
where it is the primary goal of the health care to provide to deliver care as rapidly and cost effectively as possible.
It was found that the ESR is artificially accelerated if the tube T is inclined from the classical vertical position. This fact was a~ready recogLused in the past as wit-nessed e.g. from te:Ytbooks such as "Clinical ~Pm~tr~ y, Fith edition" 1961 (Wintrobe) or "Todd-Stanford clinical diagnosis by lab methods'' 14 edition, 1969 (Davidsohn & Henry).
Wbile the underlying m~h~niqm is not thoroughly clear, it is felt that, by keeping the tube T inclined with respect to the vertical position, the blood cells descend along the tube waU and accelerate more rapidly than the classic vertical position, while the plasma ascends.
In the dlld~ L shown in fig.3, this result can be easily achieved simply by stopping the rotary motion of the mounting fixtvre carrying the rack 1 at the end of the mi~cing stage at a position which leaves the tube(s) T oriented d~l,U~ Ul illld~ y 20F from the vertical position.
2 ~ 80799 For that purpose reference indicia (such as a notch or an optical mark 12) can be provided on the rotary fr~ture carrymg the racks 1. Such indicia are detected byrespective sensors 12a (of known type), acting as angular position sensing means, in order to stop the rotary motion of the fi~ture at the desired angular position. An mclination amgle of about 20 was ~ idlly found to represent an optimal choice. While in principle c;~ ly different in~linqti-~nR can be used, it was found that lower angles will not accelerate the ~.~ .l;,....,l,,l.,-)n rate as much and have been seen to result in poorer reproducibility of the ~a<lbult~ . Higher anglesofferslighth-~ l.lDintherateofqP~imPn~ti~n~butcreatedistortion for the optical viewing device (e.g. the camera 3) in sensing the specimen, parti-cularly in the area of the blood/air meniscus defining the top of the blood column which changes shape from a circle to an ellipse in a cylindrical tube the more inclined the tube becomes. This may result in a poor Pqt~h1iqhnnPnt of the zero or base line from which the ESR .llad~ is based.
In the classic Westergren method, a 200 mm long tube is scanned after 60 or 120 rainutes. Depending upon such variables as patients' health, se~, age and haema-tocrit, it may be necessary to scan the tube for th~ ~Wplasma interface as far down as 1'iO mm below the meniscus. Because the rate at which the cells fall is verg slow, particularly in the vertical position, the operator must wait at least 60 minutes before he or she can be certain that the rate of a cell falling has effectively reached zero. The size, cost and comple~ity of an instrument to accuratelg search for and locate the cell/plasma in~erface is increased by having to e~amine such a long distance as 1~0 mm.
As opposed thereto, in the ~ I dl If;,~...."...~ of the invention a much smaller length or "window" W of the tube T containing the specimen is sc~mned.
In the solution of the invention for prospected use in the e~emplarg automated ESR .1~1. . ,.,;,.-1;, apparatus disclosed in the foregoing a short blood collection tube (about 80 mm to about 110 mm about 80 mm being the presently preferred value) is used whereby a blood column may be formed therein having a height of not less tham about 75 mm and not more than about 105 mm. The tube is pre-ferably inclined at ~ b~laiGly 20 to accelerate the rate at which the cells fall, making it possible to read significant ~ in the cell/plasma interface sooner than 60 minutes ~preferably about 20 minutes or less). In addition, the optical viewing device is sized or adjusted only to read a short length (30-40 mm or less contrary to 70-80 mm of the SEDISCANR system) of the tube T located at the top thereof, "at the top" meaning a lerlgth or window W which ~ the blood/air meniscus in the tube T upon starting the test or has its upper margin lower than the blood ~lil/lllG~ b and located in proximity thereto.
It will be .I~l GclilLGd that, in the e ~emplary ~ 1 o~l; " .. .~. of the invention shown, ~ierl~- PmPnts in the cell/plasma interface are simply read or viewed by the camera 3a without any vertical 6canning moYement along the test tubes being required.
In a thoroughly ul.G,.~,c~Led manner, it was found that by restricting the distance the cells have fallen to said reduced length W and at said periods, the observedvalues are lG~ ,..., O~Li~G - with a high degree of reliability and repe:lLdbility - of the desired ESR values. (~ y, by L~ r.,l ~ .g the observed values, final values can be found which closely match the classic Westergren values.
Preferably, if the cell/plasma interface remains in the viewed length W for the entire test period (2C minutes or less), the final observed va~ue arG us~d for cor.-~er-sion to the classic Westergren value. Also preferabb, if the cells have fallen at such a rapid rate, that the interface is outside of the length W before the end of the total test period the previous observed reading whicb fell within the viewed length W
is used for conversion to the classic Westergren value. Thus, by observing only a small portion of the tube below the blood/air meniscus and converting the observed value to a classic Westergren value in far less than 60-120 minutes, the invention provides a solution for giving thoroughly reliable results to the patient in a much faster period than in the past.
`~ 2180799 As indicated in the foregoing, attempts were already made in the past of using shorter test tubes (i.e. shorter blood columns) and/or providing results in a shorter tiune than the standard 60-120 minutes of the Wester~ren method. None the less, these past methods require the who~e blood column, or a s--hqtant~'ql portion there-of (about 70-80%), to be scanned in order to obtam reliable results.
Contrary to any reasonable ~rrt~ tirn, the solution of the invention provides for cell falling being monitored only over a reduced length or window of the blood column in the tube while providing thoroughly reliable results even if the overall period the cell falling ~ is observed is reduced to 20 minutes or less.
Another less apparent, but egtremely important advantage of the solution of the invention, is that because the window W is only a portion of tbe entire tube length (see especially fig.l) the remaining tube length can be used to apply patierlt ;d~ntifirqtion labels L to ensure the diagnostic result is properly matched by the laboratorian to the correct patient This is particularly important as the use of bar code style positive patient idrntifirqti~n labels L adapted for reading by manual scanners, such as scanner 10, has increased rapidly in an effort by hospitals to im-prove quality of care while increasmg laboratory effficiency and throughput. These labels L are typically a 30-50 mm long (in the a cial direction of the tube T). When these labels L are applied to "short" blood collection tubes T intended for ESR
~ t~rminqtir,n theywouldcoversuchalargeareaofthetubeTthatisnotposslble to observe the meniscus or the interface in order to make the ESR ~-ea~u.~ ,.t.
As a result, these labels cannot be used or must be removed or the specimen mustbe Ll~dLled over to another tube T or pipette in order to make the ESR determi-nation, or require (as is the case of the Diesse VESMATIC system referred to in the mtroductory portion of the description) to provide for an additional plastic outer sleeve to apply patient bar code or i~ntifirstirn labels This increases the opportu-nity for error, takes time, costs more money and/or e~poses the labol~L~ to a blood specimen uLIl)e~ u ily.
CU~ U1U~ LIYt the present invention provides the significant advantage of being able to apply typical labels L onto the exterior of a primarv tube for an ESR
,l~l. ."i~. -l ... in an area (the lower portion of the tube T shown in fig.1) which does not obstruct the ~ u ~ . This is essentially due to the fact that - accord-ing to the rnvention - only a minor portion ("minor" meaning about 60% or less, typically about 30% or less) of the blood column within the tube T is actually used for ~1~1...., i, .~ ~.io., The remaining lower portion of the blood column, while playing a role in the overall cell faLing pl ~ A, can be covered by the label L as it will not be used for .1.~. ",;,.,,I , purposes.
In order to provide the clinician with an estimate of the classic Westergren value when using a short tube length and observing only a small portion of the tube and when providing a reading in 20 minutes or less, it is necessary to utilise a mntl7.omnti~-nl algorithm to establish the relation of the observed reading to the Westergren value Such an algorithm was ~,u~ ., u~,~ed using extensive ~data. The resultin~ system was then examined by companng actual 60 and 120 minutes Westergren values versus extrapolated Westergren values as predicted by the mnthfn~irnl algorithm.
Specifically, to establish the r~lAti~nel~ip~ specimens from a large population of patients ~n=10 l) admitted for hnepitnli7~ m or seeking medical care were analys-ed by both the Westergren reference method and by the system. The ~.,.1;, ., ~, . ~ ~1 l . .
rate e~l,re~sed i~ n~m/hr for the Westergren reference methûd was collected using the standard glass pipette at the specified time intervals of 60 and 120 minutes after initiation of the test Meanwhile, in parallel, using the iu2,~ u~, . ~ and tube previously described, the initial blood meniscus height in the tube at time 0 was 1y~ the location of the cell/plasma interface was observed via the camera system and measured by`the instrument. This data was collected at intervals of abûut 10, 15 and 20 minutes after the initial time.
Using a linear regression analysis, this data was first amalyzed graphically by ~ 2 1 80799 Lhlg ILe observed value at each time interval versns the reference method value and ~ e the correlation. An erample of this data may be seen in figure 4.
This shows that the correlation is reasonable ~R2=0.7088) as the flow data is actual-ly non-linear. It was also confirmed that all of the observed ceWplasma merliscus had fallen less than about 38 mm from the initial starting blood column height of ly 82 mm (46%). From this it was confrmed that in the system of the invention the ,~.l;, ,l,,~ rate of the cells is such that it is possible to predict the Westergren value in 20 minutes or less. From this it was also confirmed thatrather than observing a substantial length of the tube (i.e. 75% of the blood column height), that the blood/cell meniscus need only be observed at the 10, 15 and 20minute time intervals within only appror~imately the upper 50% of the blood column height for nearly all the blood specimens. Therefore, it was not necesgary to use the lower portion of the tube for observation.
To further enhance the quality of the correlation achieYed by observing only a limited portion of the blood column height at time intervals no later than 20 minutes after start of the test, non-linear polynomial algorithms were then chosen.
In addition, it was learned that the correlation can be further enhanced by using two sets of such algorithr~s depending upon the initial column height of the tube.
Tubes which were properly filled, in our case at greater tharl about 80 mm are analyzed using one algorithm to predict the Westergren value while tubes filled less than about 80 mm are analyzed using a second algorithm to predict the Wester-gren value. An eZcample of this data ma~ be 3een in figure 5. Using a multip~e part non-linear algorithm described in Tables 1 and 2, the observed data was converted and it was u~ ,.dl~d that the correlation was improved (R2=0.7536) and that the flow of data now follows the regression more closely.
., To further enhance the quality of the correlation, clinical investigations were expanded to cover a population of 339 patients at multiple sites. The resulting algorithm is defined in Tables 1 and 2.
Table 1 AlForithm for l~redictin~ the 60 minute WesterFren value when blood column heiFht i8 greater than 80 mm.
* If cel31plasma meniscus (i.e. intêrface) has falIen <36mm at 20 minute reading interval:
Predicted value (mm/hr) = (0.652194*A)+(0.04552~*A2)-(0.06051*C2) * If cell/plasma meniscus has fallen >35mm at 2o minute readi~ v al but <3~mm at 15 minute reading interval PrediGted value (mm/hr) = (3.229994#B)-(0.0758*C2) * If cell/pla$ma meniscus has fallen >35mm at 15 minute reading interval but <35mm at 10 mmute reading interval Predicted value (mm/hr) = (5.634304*A)-(0.07907*C2) Al~ rithrn for PredictinE the 60 minute WesterFren value ~hen blood column hei8ht is les8 than 80 mm.
* If celllplasma meniscus has fallen <30mm at 20 minute reading interval:
Predicted value (rnm/hr) = (0.652194*A)+(0.046525*A2)-(0.06051*C~
* If cell/pla$ma rlerriscus bas fallen >30mm at 20 minute readmg interval but <30mm at 15 minutê reading interval:
Predicted value (mmlhr) = (3.578074*B)-(2.1702*C2) * If cel3/plasma meniscus has fallen >30mm at 15 minute re~ ding interval but <30mm at 10 rnirlute reading interval P e~icted value (mm/hr~ = (5.509347*C) (0.08674*C2) Where:
A = observed reading at 20 minute interval B = observed reading at 15 minute interval C = observed reading at 10 minute interval Table 2 AlForithm fgr gredictinF the 120 minu~e WestêrFrên value when blood column ` ~ 2 1 80799 hei~ht is ~reater than 80 mm.
* E ceWplasma meniscus has fallen <35mm at 20 minute reading interval:
Predicted v2~ue (m~/hr~ s ~6538353(j4'A)~(0.021903042-A') (~
* EceWplasma meniscus has fallen >35mm at 20 minute reading interval but <35mm at 15 minute reading interval Predicted value (mmlhr) = (4.625610738~B)-(0.07Z863681*C2) * Ecell/plasma menificus has fallen >35rrm at 15 minute reading interval but <35mm at 10 mmute reading interval Predicted value ~mm/hr) = (q "95qC'-~a~*C)-~0.162433073*C2) Al~orithm for Predictin~ the 60 minute Wester~ren value when blood column hei~ht is less than 80 mm.
* E cell/plasma meniscus has fallen <30r m at 20 mmute reading interval:
Predicted v2~ue (rcm/hr) = (553836364~A) ~ AZ)-(4 ~
* E cell/plasma meniscus has fallen >30mm at 20 minute reading interval but <30~un at 15 minute reading interval:
Predicted value (mm/hr) = (5.527322594~B)-(2.740388301*C2) * If cell/plasma meniscus has fallen >30mm at 15 minute reading interval but <30mm at 10 minute reading interval Predicted value (mmlhr) - (9.66013q741*C)-(0 Where:
A= observed reading at 20 minute interval B = observed reading at 15 minute interval C = observed reading at 10 minute interval The correlation results achieved behqeen the predicted value and the Westergren reference method may be seen in figures 6 and 7 (R2=o.93 for 60 minute Wester-gren value and~ R2=o.94 for 120 minute Westergren value).
It will be easily ~yy~ ed that ihe various parameters considered in the fore-going (i.e. the 80 mm blood column height, the 35 mm distance fallen, the 10, 15, and 20 minute reading intervals), while rrmFtit.~tir~ preferred choices at present, ` ~ ` 2 i 80799 do not represent absolute imperative values. For that reason the wording '`about"
was resorted to in the annesed claims in respect of those p~et~.~ in order to make it clear that any possible minor changes, with respect to any of those para-meters wiU not invalidate the espected results.
Also, it is entirely possible to develop alternatives to the algorithm presentedherem that may be equally as effective. For eYample, the reading mtervals can bechosen to be more frequent or less frequent tham the 10,15 and 20 minute intervals described here. Consequently, the preferred coefficients disclosed in Tables 1 and 2 may vary ac~,~"d~&ly. The system described here provides predictions after 20 minutes for the ~Ve, le, ~ l e l~ value classically obtained using the reference method after 60 and 120 minutes. The new system clearly offers significant advantage tothe user by providing diagnostic values faster to the clinicians. By shortening the reading cycle further through the d~ lle~lt of alternative algorithms in the manner described herern or in similar manners, it would further add advantage for the clinician.
It is also entirely possible to develop algonthms with mathem- tical corrections for environmental factors encountered during the test. Such factors may include the laboratory l~ I as it is weil r ~=~liqh~l that increasing ~II~ can accelerate the g~ rate.
aiso posslble to develop algorithms w:th .,...~ l correction for patient factors affecting the blood specimen. Such factors may include the patient haemato-crit as it is well f.qfqhliqh.~ that decreasing haematocrit can accelerate the ædi-mentation rate.
,~
It is also possible to develop algorithm3 to achieve the desired correlation if one were to use specimen collection tubes of geometries and volumes or with additives other than described herein. For eYample: alternative surfact~mt; alternative citrate anticoagulant to blood ratios; alternative q n ti~q~l I qn tq such as EDTA, heparin or -` ~ 2t 80799 hirudin; alternative tube diameters, shapes or lengths. Changes to any of these factors is likely to make the algorithms described herein less optimal. However,usmg the method described herein or similar methods, new algorithms can easily be developed, without undue ~ .. being required, the key point being the recognition that the values obtained according to the invention are representa-tive - with a high degree of reliability and repeatability - of the desired ESR values.
Consequently, the values obtamed can be converted, through a given ~ ,. .,L~
(as the algorithms disclosed in the foregoing) to the classic Westergren values.
Also, it will be easily d~AV~ d that any conversion algorithm as those disclosedand/or referred to in the foregoing may be easily stored and;, ~ l (in a thoroughly known manner) in a computer such as the computer designated 11 rn figure 3 As mdicated, even though the test tube of the invention was devised for preferred use in a fully automated ESR determination method and apparatus, thoroughly satisfactory and reliable use was also ~ 1 with in a "manual" version of the ESR determination method wherein reading is s~ 1 by eye and re-quires a stand (not shown) to hold the tube vertically during a 60~120 minute reading perioa. On the stand i8 a scale read by eye in the lo~rithnnif format which converts the observed value directly to that ~ntirir~ted by the Westergren method.
The test tu~e for use in this manual version is similar .n al.l regarcls to the test tube for use rn the automated ESR (il~tPrmin~tiOn procedure described in the fore-going eYcept that a tube wall length of about 110-120 r~m, preferably about 120 mm, to yield a blood column height of nominally about 100 mm was found to be preferable. The resulting blood draw value is about 2.3 mls. The additive type, surfactant and other tube geometries are other~vise the same. As the tube is read preferably as much as 75% of the tube length, ~v~ v~vi~.~;ly shorter patient .,. data labels are usually applied at the bottom end of the tube.
46: 198-203.
Essentially, the Westergren method provides for a sample of blood to be collected in a test tube (pipette) to form a 200 mm blood column in the presence of an anti-coagulant. A~ter mi~cing the specimen briefiy, the test tube is loaded into a device or an ~lAL U~l~ including sensors such as an optical sensor to record the location of the blood/air meniscus at an initial time. A~er a period of 60 or 120 minutes, the operator or the sensor then identifies and measures the location of the cell/plasma interface. The distance in millimetres from initial blood/air meniscus and the final cell/rla~m~ int~rface gives the typical Westergren output value for the test which is e pressed in units of mm/hr.
A basic disadvantage of the cu., ~ iu~l~l Westergren method lies in the consider-able length of the test tube (typically in e2~cess of 200 mm) which makes it un-suitable for Ise in collecting blood directly. Consequently, blood for t;.e test has to be taken either by using a syringe or a pre-evacuated tube and the blood thus collected must then be lA~ to the Westergren test tube. In addition to being 1~nr~ti~1 guch a procedure expoges the operator to the danger of contacting the blood during the transfer process.
Systems dispensing with such a drawback and carrying out ESR ~ . . .; . . ,. t: - . us-rng tubes ~ l ly shorter than the standard 200 mm Westergren pipette are already available.
Exemplary of such prior art is, for instance, the ESR measuring system sold under the trademark SEDISCAN by the assignee of the present ~rFIir~t;rm A SEDI-SCAN illai.lUlU.,.~ is adapted for use in connection with tubes (sold under the trademark SEDITAINER - both SEDISCAN and SEDITAINER being registered Il ad~ al 1. h of Becton Dickinson and Company) essentially comprised of 6 ml draw tube of 120 mm length and 10.25 mm outer diameter containing liquid sodinm citrate/citric acid at 4:1 ratio. Using the above tube, the SEDISCAN ~ u~. .
provides an e~trapolated Westergren value after 30 minutes which compares well to actual 60 and 120 minutes Westergren values. However, it is necessary to e~amine nearly the entire tube length (about 70-80 mm of the blood column heightof 100 mm) in order to predict the ESR The tube is held verticalb.
Another system using "short" tubes is sold under the trade name VESMATIC by the Italian company Diesse Diagnostica Senese S.r.l.. The tube for use in this latter system has a rectangular shape overaL amd a triangular shape of the tube bottom.un, nearly the entire tube length must be scanned which leads to using an additional plastics outer sleeve to apply patient bar code or i~l~.,l.;l';. -1;~", labels.
The outer sleeve and the patient i~ntifi(~tl~ln data must be removed from the tube before this is placed in the instrument for carrying out the test. Cu~e~u~l-Lly, the-re is an actual danger that, due to the high number of tubes tested ~UU~.UUl~.lUy in a laboratory, a diagnostic result may be incorrectly assigned to the wrong patient due to a mistake in association of the clinical result for a tube with the patient irl~ntifi~t.i~m con~ined on the removed outer sleeve.
So, it is practically a mandatory I~U,Uil~ for any test tube for proper use m ESR measuring test to carry patient ;,1 ., I i l i. ~: . data which must not and cannot be removed at any time, while carrying out the test.
Also, there is a growing trend in the field of ESR ~ -- to provide reading ofthetestfinalvaluesina~,~,.,;l';~..-ll.lyshortertimethanthestandard60minutes of the Westergren method. Finally, the quantity of blood required for the test ~and ~ ~ ~ ` 21~8GZ799 y the qu~mtity of blood to be taken from the patient) is to be made as smail as possible.
The present imvention basical;Zy a,ims at providing a solution which joint,iy over-comes the drawbacks of the prior art solutions, i.e. by providimg an ESR determina-tion prooedure, where:
- ~short" tubes are used, preferably adapted for direct blood col;Zection;
- patient irl~ntifi~ data, once applied onto the tube, cannot be removed from it, thereby making it impossible to dis-associate the specimen from the patient - reiiable ESR values are provided in a term much shorter then the standard 60 or 120 minutes of the Westergren; and - the quantity of blood to be taken from the patient is min;mie~
A method and apparatus whicLZ permit reZiable ESR values to be provided in a short term (e.g. 20 minutes or less) Wil;Z be described in the following which constitute the subject matter of a European Patent appZication filed on an even date by the same Applicant of the present ~rrlil-~ti~n ~ -Specifica;Zly, the invention relates to a test tube ~ ",g an i~ over the prior art as i~Y~mr! fi^~l by the SEDITAINER~ test tube referred to in the fore-going .
Essentially, the underiying problem of the invention is providing an improved test tube by means of which the resuits obtained by the captioned new method and apparatus may be optimized. According to the present invention, that problem is solved by means of a test tube having the features set forth in the claims. The imvention a;Zso relates to a surfactant for use im such an improved test tube.
In the presently preferred ~ G-~ . of the invention, a ~ u~ed test tubeis used to collect ~e specimen which is made of such a material as glass or plastics and which contains an ~ v ~ The tube is then put into a rack and loaded mto an i~ llell~ which mixes the specimen briefly. The i~L ~ then uses optical sensors to record the location of the blood/air meniscu~ at an initial time.
At ~ time intervals thereafter for periods up to 30 minutes, typically 20 minutes or less, the optical sensors then identify and measure the location of the cell/plasma mterface. These measured values are then converted by a given ,,. T ,I e.g. am algorithm, to the values which would be obtained using the classical Westergren method (200 mm blood column height and blood to citrate ratio of 4:1).
When a small bore evacuated blood collection tube containing am a~ ,vp~ vlal 1 ~ is used several ~ , should be preferably satisfied in order for the tube to function in a most ~ali~ra~vly way. These requirements are as follows:
- the anticoagulant must be rapidly mi ~ed with the blood sample at the time of draw to insure a full anticoagulation effect;
- the tube must contain a thoroughly l~ "Pv l~ suspension of erythro-cytes prior to setting up the ESR test in order to obtain optimal results;
- the additive/anticoagulant mu~;t not interfere with the hslP~3tr parameters of blood In the invention, in order to sati~ly the first two ~ , a surfactant is added to the tube to promote rapid mi~cing of the contents by reducrng the surface tension of the blood sample to the glass tube. This allows for adequate anti-coagulation of the blood specimçn during draw. In addition, the amount of mi~ing(ie. agitation or stirring) required to insure a 1 . ~ suspension of erythro-cybs during ESR set up is reduced because the tube mi~es faster which in turn causes more turbulence within the tube thereby stirring the specimen.
Generallythereisan~l.. ,1;~1 l~la~lullaLubetweenmilbngtimeandconcentra-tion of surfactant, and at a~uulu~hlla~ely 1% by weight the fasbst mi~ing time was found to be achieved.
2 1 ~
A similar ~rrnr PntiAI lel.l~iu~L~ was fûund to êxiSt between mi~ing time and diameter ûf the glass tube. Due to the use ûf the surfact~mt a 6mm inside diameter, 8 mm ûutside diameter tube was found to mr almûst as fast as an 8 mm irside diameter 10 mm ûutside diameter tube withûut the use of the surfactant.
Briefly stated the key physical property that the surfactant must exhibit is thelowering of the surface tensiûn of whole blood to the glass tube. The surfactantmust alsû nût interfere with the 11A ~ y prûperties ûf human bloûd. Fûr elcample, the surfactant must not effect the alpha-globulin interaction with erythro-cytes as this is a key factor in erythrocyte ~.~.l;,,.~,.lUl .... rate testing (ESR).
The surfactant must alsû preferably be:
- irradiatiûn stable, thereby allûwing Cobalt 60 ~tPril;7AtiAn of the tube;
- chernically stable e.g in a buffered Tri-sodium citrate anticoag lIant;
ut,ld~ stable over the desired range of use, as well as during the transit ûf the product from the plant of the customer.
For e ample, somP ~ b were found to become irreversibly cloudy in the citrate anticoagulant when heated above 50C This is perceived as a fungal/bacte-rial growth in the tube, and is ~]nû-~Ppt~hlP
Desirably, the surfactant is a noniûnic surfactdnt. An example of such a surfactant isanor~An~A. ili~nP Preferably,theul~ il; r IPiS apolyalkyleneoxidemodified pûlydimethylsiloxane. Polyalkyleneor~ide modified p~ly~ llyl siloxanes are foundto be stable with irradnation, do not cause the blood to haemolysis and increases the rate of mixing ûf the blood sample.
':
In a thoroughly ull~ d manner, the solution of the invention was found to be suitable for satisfactory and reliable use also in a ~manual" ESR d~ iiu..
procedure, wherein the test tube is held vertically during the standard 60-120 minute period and reading is A. . . IIII;A~ IP~l simply be eye against a reference scale.
~ ` 2 ~ 80799 The invention will now be described, purely by way of er~ample, with reference to anne~ed drawmgs, wherein:
- figl shows a test tube according to the invention, - figs.2 and 3 show L.16~ lly the typical ~ul~6~ -1 of device of the invention, and - figæ.4 to 7 show the correlation between the results of the method of the invention and the results which would be obtained using the classical Westergrenmethod.
In fig. 1 an exemplary tube according to the invention is generally designated T.
Such a tube T - intended to define a cavity for forming a column of blood whose ESR is to be determined - has a tubular, preferably cylindrical wall with an outside diameter of not less than about 7 mm and not more than about 9 mm. The length of the tube T (roughly ~u~l~,UUl~Uillg to the height of the blood column formed therein which is preferably not less than about 75 mm, but not more than about 105 mm) is preferably about 80 mm. The inside diameter is preferably not less than about 5 mm and not more than about 7 mm and still preferably about 6 mm.
. .
IL L~Iue~ of the specific ~" .T .r,.~; . . .~" t, the inner diameter of the tube T must be ic;~Uy large to allow the blood specimen used for the test to mir adequately ;.,.",a.~ ly after co31ecting to ensure complete ~uti~,uz-6ulaLul- is achie~-cd. Sub-sequently, imrnrrTi~taly before initiating the me~ul~u~llt of the ESR, the speci-men must be uniformly and completely mr~ed to re-suspend ,blood cells.
The inner diameter and tube length should also be sufficiently small to minimisethe volume of the blood required from the patient for the test, since excessive blood lost by patients is considered rl~ :., ;, . . . I ~l to their health. This is particularly the case for paediatric patients who have small blood volumes amd geriatric patientswho have diminished capacity to regenerate blood cells. In the ~,U~UUdtiUIl described, blood I ~U Uil ~ i would be typically less than 2 mls which is cûnsider-ed ~ulTi~,icuUy small to have little impact on patient health.
The outer diameter and tube wall thickness must be sufficiently large to add sufficient strength and rigidity to ensure the tube does not break or bend during hamdling and ~ . testing. However, they should be ~ .ie~l~ly small to ensure the tube is easy to cut, form and glaze as in the case of a glass tube orinjection mouldea as m the case of a plastics tube. Excess material leads to higher m~n~ t--r~n~ cost and an overly thick tube wall could reduce the ability of an optical viewing device to see through the wall when attempting to identifying the meniscus amd the interface.
Optical imagmg devices, such as a LCDs, linear CCDs and video cameras, are pre-ferably used in connection with a visibly ~ tube wall (at least insofar as the "wmdow" of the tube actually observed is concerned), e.g. made of glass or plastics Alternative ~ ltq can however be envisaged~ wherein non-optical/sensors and/or visibly opaque, non-transparent tube walls are used.
E~emp~aryofsuchalternative~mhqrlimPnt~areimagingdevicesoperatingoutside the visible range (e.g infrared radiation) or devices operating with other kinds of radiation or based on other physical rh~n~;n~n~ (e g. capacitive sensors and thelike) Optical devices are however preferred due to the current availability of devicesadapted for use within the framework of the invention. E~cemplary of such devices are, in addition to the one used in the assignee's SEDISCANR system, those sold under the trade names Sony CCB-~q25/CE (CCD) and Sony PSB9151A (~w~r board) [Sony, Kanafawa, Japan] and Computak 6mm 1:1-2 1/2" C (Lens from Japan).
The open end of the tube T is preferably sealed by a stopper S having vacuum andmoisture barrier prqperties suitable to maintain the additive contents and blooddrawing capability for periods in el~cess of two weeks and preferably for periods in excess of one year.
The tube T according to the invention may be packaged and sold as a stand-alone,disposable, product comprised of the tube body proper (made of glass or plastics, for instance) pre-evacuated and sealed by the stopper S and also including a quantity of additive A Primarily, the additive is intended to act as an anti-~ tin~ agent/mixing aid.
Preferably, the additive is a mixture of triffodium citrate (Na3) and citric acid mixed in an aqueous solution to achieve a molarity of 0.105 M-0.135 M. Sufficient solution (e.g. 0.46 cc - referring to the preferred dimensions of the tube T referred to in the foregoing) is dispensed into the tube T during ."~".,r,.. ~... ;..g in order to ensure a blood to additive ratio upon specimen collection of 4:L However, when using liquid citrate solutions, blood to additive ratio starting at about 2:1 and below and up to about 10:1 and above are possible; the m~th-~m~ti(~l algorithm which converts the observed rate of cell settling to the claffsical Westergren value is adapted accordingly. Likewise, alternative anticoagulants such as EDTA Hiru-din and its analogues or potassium and sodium oxalate can be used in a variety of forms, such as liquid, freeze dried, powder or spray coatings. Each may be equally effective in anticoagulating the specimen without haemolysis and with an appro-priate ".~ 1 algorithm will allow conversion of the observed value to the Westergren value. Non-liquid, e.g. dry additives are usually preferred in the case of plastics tubes due to the well-known tendency of plastic tube to lose moisture.
Aso, to further enhance and facilitate mixing of the specimen in the tube irrespect-ive of the ~im~nqionq thereof, a component which reduces the surface tension of the blood is added to the tube as a coating or combined with the anticoagulant in its liquid or dry form. Desirably, the surfactant is a nonionic surfactant. An example of such a surfactant is an or~n~ilirnn~ Preferably, the or~n~-sili~ n-~ is a polyalkylenoxide modified polydimethyl-giloxane. Polyalkyleneoxide modified poly-dimethyl siloxanes are found to be stable with irradiation, do not cause the blood haemolysis and increases the rate of mixing the specimen to provide a well anticoa-gulated amd hulllu~ eou~ gpecimen without celi ~A~aliu.l or clotting.
2 ~ 80799 The fastest r~i~ing time was found to be achieved at ~ J,UI u~ aluly 1% cûncelltra-tion by weight.
Fig2 and 3 show a rack l adapted for receiving o.ne or, preferably, a plurality of tubes T, a light source 2, such as a 11 uu, ~c~, light arranged on one side of the rack l to create b~lu~d i1111minqti~m, as well as am optical ~naging device suchas a video camera 3, arranged on the other side of the rack l and adapted for viewing, as better described in the following, the tube or the tubes T against the background illllminqti~n created by the 30urce 2.
The location of the cell/plasma interface (c~-hGmqtirqlly designated I in fig.2~ is thus detected as a contragted image (dark/clear, black~white) against said background ilT~lminqti~n In the preferred l~mhofTim~nt shown in fig.2, the rack I is essentially comprised of a C-shaped frame having opposite lower 4 and upper 5 arIns adapted for securely receiving the lower and upper ends of the tube or tubes T. The two horizontal arms 4, 5 are connected by an upright arm 6 which is rigidly fi~ed to one of the arms (for instance upper arm 5) and is hinged at 7 to the other (in the present instance low-er) arm 4. Tbis ~ 1 ~u~ i permits the rack l to be opened to insert the or each tuT~e ~ into respectivc cavities ~ provided in the lower arm 4 and then securelylocked to their final position for carrying out the test by bringing the rack l to its closed pOsitioff wit~. the upp~r arm 5 (having respective cavities or a cutout on the lower side thereof - not visible in the drawing) to engage the upper ends of the tube or tubes T (cTosed by the stopper S). The racl~ I is then locked to its closed position by means of a lock m~r~qnicm controlled by a thumb-actuated slider 9.
,~
According to an dl 1 ~14~ well-known per se, the camera 3 has associated there-with drive means (6uch as a motor-driven toothed belt 3a) which cause it to under-go a traYerse movement (as shûwn by the double-pointed arrow of fig. 3) along the tube or tubes T. The motor moves the camera to view each rack (three such racks `~ 2~80799 Are provided in a linear array in the currently preferred ~.~\ho.l;.. ,.-,.t of the inven-tion). The motor does not move the camera during the period when the camera is viewing a specific rack. The cAmera sees a 2~im-~nC;~nA~ picture of the rack andthus can see the entire aspect of each tube in a rack After reading one rack thecAmera is moved by the motor to view the ne~t rack Also, associated with the rack 1 is a rotary mounting fi~ture including a rotAry platform or drum D carrying supporting formations which enable the rack 1 to be safely retained on the mount-ing fi~ture as this is rotated about a horizontal a~is ~ under the action of motor means (not shown). Thus, the rack 1 and the tube or tubes T located therein to be vertically rotated about an axis ~ to achieve thorough miring of the specimen im n..iiAtPIy before initiating the optical reading The rack 1 also allows the tube or tubes T to be optically observed from the side st-Arting ;, - ~ y above the blood/ air meniscus and continuing downward over a distance defining a window W as e~plained irl detail in the following Even though preferred at present, the rack, . I ~,~t,, . ~ described in the foregoing is not - per se - critical to the invention. Other ~.,.,.~;. .,~ .1.~ such as the one current~y used in the SEDISCAN~ system, can be used. I~nis also applies to the nature of the imagmg device embodied by the video camera 3. As an alternative toLCDs, linear CCD arrays and other devices (including non-optical devices) may beused.
Also, the arrangement for causing the camera 3 to move along the rack array, as well as the rotary mounting fir~ture for the racks 1, are ~ v~ al in the art anddo not require to be described in further detAil.
The foregoing also applies - in general terms - to the computer~conhrolled arrange-ment adopted for processing the output signal from the camera 3 and the possi-bility of usmg a mamual scanner 10 for identify-ing each and every tube T as it is loaded into the respective rack 1. The manual scanner 10 enables each patient's nhfirAt.~n data (usually in the form of a bar code) to be read from a label L
2l80799 apphed around the lower portion of eaeh tube T when collecting the blood samples.
Both the output signal (which is usually eonverted to a digital format) as well the signal from the manual seanner 10 are fed to a data processing unit, such as a personal eomputer 11. As an alternative to a y~ general purpose eomputers, a dedieated eomputer or proeessor ean be used. Suitable y~ o~ g (aceording to well-known eriteria whieh are not required to be deseribed here) enables each tube T to be safely identified as sueh, prior to loading into the instrument, while the respective camera reading 3, converted to a standard Wester-gren value, ean be outputted as a visual display on a sereen and/or a hard eopy printout or ~ P~ electronically to the host computer managing patient data in the laboratory. For a general review of the general prineiples of operation of sueh a proeessing unit, reference may be made to the User's Guide to the SEDIS~ software available with Becton Dickinson Vacutainer Systems and Cell Seience Product Europe for use with the SED~SCANR measuring system. Further details concerning the algorithm adopted for converting the camera reading 3 to standard of Westergren values are provided in the following.
When a plurality of tubes (such as fifteen tubes) T are tested simultaneously in a raek, these are preferably arranged in the rack in an array including two parallel rows, as shown in fig.2, with the tubes T in the adjacent rows suitably staggered or offset in order to make sure that all the tubes T in the two-row array can be ins-pected by the camera 3 moving along a line parallel to the two rows Preferably, the locations of the tubes in each rack 1 are such that all the tubes in the raek can be inspected ~im~ nPo~ y by the camera 3 positioned at a given pomt with respect of the rack 1. That point is preferably chosen to eorrespond to a central positioning of the camera 3 with respect to the length of the raek.
As the tubes in each rack 1 can be viewed .cirn~ nP-mcly by the camera 3 from a single location, the camera 3 needs to be stopped only once for eaeh rack, without any scanning movement being required. In the presently preferred ~ I,odi~ of `-- ` 21 80799 the invention7 three racks are arranged to be tested hi~ v~ y~ and the movement of the camera 3 along the guide 3a is thus stopped three times. Suitable controls may however be provided in order to prevent the camera from stopping atamy location where, for any reasons, no rack, a rack containmg no tubes or a rack containing only empty tubes are arramged.
From fig.3 it will be dl)lVl~d~td that, in the preferred ~ vl;~ of the invention, the tubes T are held inclined at an angle o with respect to the vertical.
As the classic Westergren method specifies that the specimen be e~amined after remaining vertically upright for 60 or 120 minutes, the cliniciam or laboratorian must wait this long before providing a diagnostic result for the patient. This mevitably results in in~t'li~iPn~ and high costs in the health care ~., vi- Vlllll~
where it is the primary goal of the health care to provide to deliver care as rapidly and cost effectively as possible.
It was found that the ESR is artificially accelerated if the tube T is inclined from the classical vertical position. This fact was a~ready recogLused in the past as wit-nessed e.g. from te:Ytbooks such as "Clinical ~Pm~tr~ y, Fith edition" 1961 (Wintrobe) or "Todd-Stanford clinical diagnosis by lab methods'' 14 edition, 1969 (Davidsohn & Henry).
Wbile the underlying m~h~niqm is not thoroughly clear, it is felt that, by keeping the tube T inclined with respect to the vertical position, the blood cells descend along the tube waU and accelerate more rapidly than the classic vertical position, while the plasma ascends.
In the dlld~ L shown in fig.3, this result can be easily achieved simply by stopping the rotary motion of the mounting fixtvre carrying the rack 1 at the end of the mi~cing stage at a position which leaves the tube(s) T oriented d~l,U~ Ul illld~ y 20F from the vertical position.
2 ~ 80799 For that purpose reference indicia (such as a notch or an optical mark 12) can be provided on the rotary fr~ture carrymg the racks 1. Such indicia are detected byrespective sensors 12a (of known type), acting as angular position sensing means, in order to stop the rotary motion of the fi~ture at the desired angular position. An mclination amgle of about 20 was ~ idlly found to represent an optimal choice. While in principle c;~ ly different in~linqti-~nR can be used, it was found that lower angles will not accelerate the ~.~ .l;,....,l,,l.,-)n rate as much and have been seen to result in poorer reproducibility of the ~a<lbult~ . Higher anglesofferslighth-~ l.lDintherateofqP~imPn~ti~n~butcreatedistortion for the optical viewing device (e.g. the camera 3) in sensing the specimen, parti-cularly in the area of the blood/air meniscus defining the top of the blood column which changes shape from a circle to an ellipse in a cylindrical tube the more inclined the tube becomes. This may result in a poor Pqt~h1iqhnnPnt of the zero or base line from which the ESR .llad~ is based.
In the classic Westergren method, a 200 mm long tube is scanned after 60 or 120 rainutes. Depending upon such variables as patients' health, se~, age and haema-tocrit, it may be necessary to scan the tube for th~ ~Wplasma interface as far down as 1'iO mm below the meniscus. Because the rate at which the cells fall is verg slow, particularly in the vertical position, the operator must wait at least 60 minutes before he or she can be certain that the rate of a cell falling has effectively reached zero. The size, cost and comple~ity of an instrument to accuratelg search for and locate the cell/plasma in~erface is increased by having to e~amine such a long distance as 1~0 mm.
As opposed thereto, in the ~ I dl If;,~...."...~ of the invention a much smaller length or "window" W of the tube T containing the specimen is sc~mned.
In the solution of the invention for prospected use in the e~emplarg automated ESR .1~1. . ,.,;,.-1;, apparatus disclosed in the foregoing a short blood collection tube (about 80 mm to about 110 mm about 80 mm being the presently preferred value) is used whereby a blood column may be formed therein having a height of not less tham about 75 mm and not more than about 105 mm. The tube is pre-ferably inclined at ~ b~laiGly 20 to accelerate the rate at which the cells fall, making it possible to read significant ~ in the cell/plasma interface sooner than 60 minutes ~preferably about 20 minutes or less). In addition, the optical viewing device is sized or adjusted only to read a short length (30-40 mm or less contrary to 70-80 mm of the SEDISCANR system) of the tube T located at the top thereof, "at the top" meaning a lerlgth or window W which ~ the blood/air meniscus in the tube T upon starting the test or has its upper margin lower than the blood ~lil/lllG~ b and located in proximity thereto.
It will be .I~l GclilLGd that, in the e ~emplary ~ 1 o~l; " .. .~. of the invention shown, ~ierl~- PmPnts in the cell/plasma interface are simply read or viewed by the camera 3a without any vertical 6canning moYement along the test tubes being required.
In a thoroughly ul.G,.~,c~Led manner, it was found that by restricting the distance the cells have fallen to said reduced length W and at said periods, the observedvalues are lG~ ,..., O~Li~G - with a high degree of reliability and repe:lLdbility - of the desired ESR values. (~ y, by L~ r.,l ~ .g the observed values, final values can be found which closely match the classic Westergren values.
Preferably, if the cell/plasma interface remains in the viewed length W for the entire test period (2C minutes or less), the final observed va~ue arG us~d for cor.-~er-sion to the classic Westergren value. Also preferabb, if the cells have fallen at such a rapid rate, that the interface is outside of the length W before the end of the total test period the previous observed reading whicb fell within the viewed length W
is used for conversion to the classic Westergren value. Thus, by observing only a small portion of the tube below the blood/air meniscus and converting the observed value to a classic Westergren value in far less than 60-120 minutes, the invention provides a solution for giving thoroughly reliable results to the patient in a much faster period than in the past.
`~ 2180799 As indicated in the foregoing, attempts were already made in the past of using shorter test tubes (i.e. shorter blood columns) and/or providing results in a shorter tiune than the standard 60-120 minutes of the Wester~ren method. None the less, these past methods require the who~e blood column, or a s--hqtant~'ql portion there-of (about 70-80%), to be scanned in order to obtam reliable results.
Contrary to any reasonable ~rrt~ tirn, the solution of the invention provides for cell falling being monitored only over a reduced length or window of the blood column in the tube while providing thoroughly reliable results even if the overall period the cell falling ~ is observed is reduced to 20 minutes or less.
Another less apparent, but egtremely important advantage of the solution of the invention, is that because the window W is only a portion of tbe entire tube length (see especially fig.l) the remaining tube length can be used to apply patierlt ;d~ntifirqtion labels L to ensure the diagnostic result is properly matched by the laboratorian to the correct patient This is particularly important as the use of bar code style positive patient idrntifirqti~n labels L adapted for reading by manual scanners, such as scanner 10, has increased rapidly in an effort by hospitals to im-prove quality of care while increasmg laboratory effficiency and throughput. These labels L are typically a 30-50 mm long (in the a cial direction of the tube T). When these labels L are applied to "short" blood collection tubes T intended for ESR
~ t~rminqtir,n theywouldcoversuchalargeareaofthetubeTthatisnotposslble to observe the meniscus or the interface in order to make the ESR ~-ea~u.~ ,.t.
As a result, these labels cannot be used or must be removed or the specimen mustbe Ll~dLled over to another tube T or pipette in order to make the ESR determi-nation, or require (as is the case of the Diesse VESMATIC system referred to in the mtroductory portion of the description) to provide for an additional plastic outer sleeve to apply patient bar code or i~ntifirstirn labels This increases the opportu-nity for error, takes time, costs more money and/or e~poses the labol~L~ to a blood specimen uLIl)e~ u ily.
CU~ U1U~ LIYt the present invention provides the significant advantage of being able to apply typical labels L onto the exterior of a primarv tube for an ESR
,l~l. ."i~. -l ... in an area (the lower portion of the tube T shown in fig.1) which does not obstruct the ~ u ~ . This is essentially due to the fact that - accord-ing to the rnvention - only a minor portion ("minor" meaning about 60% or less, typically about 30% or less) of the blood column within the tube T is actually used for ~1~1...., i, .~ ~.io., The remaining lower portion of the blood column, while playing a role in the overall cell faLing pl ~ A, can be covered by the label L as it will not be used for .1.~. ",;,.,,I , purposes.
In order to provide the clinician with an estimate of the classic Westergren value when using a short tube length and observing only a small portion of the tube and when providing a reading in 20 minutes or less, it is necessary to utilise a mntl7.omnti~-nl algorithm to establish the relation of the observed reading to the Westergren value Such an algorithm was ~,u~ ., u~,~ed using extensive ~data. The resultin~ system was then examined by companng actual 60 and 120 minutes Westergren values versus extrapolated Westergren values as predicted by the mnthfn~irnl algorithm.
Specifically, to establish the r~lAti~nel~ip~ specimens from a large population of patients ~n=10 l) admitted for hnepitnli7~ m or seeking medical care were analys-ed by both the Westergren reference method and by the system. The ~.,.1;, ., ~, . ~ ~1 l . .
rate e~l,re~sed i~ n~m/hr for the Westergren reference methûd was collected using the standard glass pipette at the specified time intervals of 60 and 120 minutes after initiation of the test Meanwhile, in parallel, using the iu2,~ u~, . ~ and tube previously described, the initial blood meniscus height in the tube at time 0 was 1y~ the location of the cell/plasma interface was observed via the camera system and measured by`the instrument. This data was collected at intervals of abûut 10, 15 and 20 minutes after the initial time.
Using a linear regression analysis, this data was first amalyzed graphically by ~ 2 1 80799 Lhlg ILe observed value at each time interval versns the reference method value and ~ e the correlation. An erample of this data may be seen in figure 4.
This shows that the correlation is reasonable ~R2=0.7088) as the flow data is actual-ly non-linear. It was also confirmed that all of the observed ceWplasma merliscus had fallen less than about 38 mm from the initial starting blood column height of ly 82 mm (46%). From this it was confrmed that in the system of the invention the ,~.l;, ,l,,~ rate of the cells is such that it is possible to predict the Westergren value in 20 minutes or less. From this it was also confirmed thatrather than observing a substantial length of the tube (i.e. 75% of the blood column height), that the blood/cell meniscus need only be observed at the 10, 15 and 20minute time intervals within only appror~imately the upper 50% of the blood column height for nearly all the blood specimens. Therefore, it was not necesgary to use the lower portion of the tube for observation.
To further enhance the quality of the correlation achieYed by observing only a limited portion of the blood column height at time intervals no later than 20 minutes after start of the test, non-linear polynomial algorithms were then chosen.
In addition, it was learned that the correlation can be further enhanced by using two sets of such algorithr~s depending upon the initial column height of the tube.
Tubes which were properly filled, in our case at greater tharl about 80 mm are analyzed using one algorithm to predict the Westergren value while tubes filled less than about 80 mm are analyzed using a second algorithm to predict the Wester-gren value. An eZcample of this data ma~ be 3een in figure 5. Using a multip~e part non-linear algorithm described in Tables 1 and 2, the observed data was converted and it was u~ ,.dl~d that the correlation was improved (R2=0.7536) and that the flow of data now follows the regression more closely.
., To further enhance the quality of the correlation, clinical investigations were expanded to cover a population of 339 patients at multiple sites. The resulting algorithm is defined in Tables 1 and 2.
Table 1 AlForithm for l~redictin~ the 60 minute WesterFren value when blood column heiFht i8 greater than 80 mm.
* If cel31plasma meniscus (i.e. intêrface) has falIen <36mm at 20 minute reading interval:
Predicted value (mm/hr) = (0.652194*A)+(0.04552~*A2)-(0.06051*C2) * If cell/plasma meniscus has fallen >35mm at 2o minute readi~ v al but <3~mm at 15 minute reading interval PrediGted value (mm/hr) = (3.229994#B)-(0.0758*C2) * If cell/pla$ma meniscus has fallen >35mm at 15 minute reading interval but <35mm at 10 mmute reading interval Predicted value (mm/hr) = (5.634304*A)-(0.07907*C2) Al~ rithrn for PredictinE the 60 minute WesterFren value ~hen blood column hei8ht is les8 than 80 mm.
* If celllplasma meniscus has fallen <30mm at 20 minute reading interval:
Predicted value (rnm/hr) = (0.652194*A)+(0.046525*A2)-(0.06051*C~
* If cell/pla$ma rlerriscus bas fallen >30mm at 20 minute readmg interval but <30mm at 15 minutê reading interval:
Predicted value (mmlhr) = (3.578074*B)-(2.1702*C2) * If cel3/plasma meniscus has fallen >30mm at 15 minute re~ ding interval but <30mm at 10 rnirlute reading interval P e~icted value (mm/hr~ = (5.509347*C) (0.08674*C2) Where:
A = observed reading at 20 minute interval B = observed reading at 15 minute interval C = observed reading at 10 minute interval Table 2 AlForithm fgr gredictinF the 120 minu~e WestêrFrên value when blood column ` ~ 2 1 80799 hei~ht is ~reater than 80 mm.
* E ceWplasma meniscus has fallen <35mm at 20 minute reading interval:
Predicted v2~ue (m~/hr~ s ~6538353(j4'A)~(0.021903042-A') (~
* EceWplasma meniscus has fallen >35mm at 20 minute reading interval but <35mm at 15 minute reading interval Predicted value (mmlhr) = (4.625610738~B)-(0.07Z863681*C2) * Ecell/plasma menificus has fallen >35rrm at 15 minute reading interval but <35mm at 10 mmute reading interval Predicted value ~mm/hr) = (q "95qC'-~a~*C)-~0.162433073*C2) Al~orithm for Predictin~ the 60 minute Wester~ren value when blood column hei~ht is less than 80 mm.
* E cell/plasma meniscus has fallen <30r m at 20 mmute reading interval:
Predicted v2~ue (rcm/hr) = (553836364~A) ~ AZ)-(4 ~
* E cell/plasma meniscus has fallen >30mm at 20 minute reading interval but <30~un at 15 minute reading interval:
Predicted value (mm/hr) = (5.527322594~B)-(2.740388301*C2) * If cell/plasma meniscus has fallen >30mm at 15 minute reading interval but <30mm at 10 minute reading interval Predicted value (mmlhr) - (9.66013q741*C)-(0 Where:
A= observed reading at 20 minute interval B = observed reading at 15 minute interval C = observed reading at 10 minute interval The correlation results achieved behqeen the predicted value and the Westergren reference method may be seen in figures 6 and 7 (R2=o.93 for 60 minute Wester-gren value and~ R2=o.94 for 120 minute Westergren value).
It will be easily ~yy~ ed that ihe various parameters considered in the fore-going (i.e. the 80 mm blood column height, the 35 mm distance fallen, the 10, 15, and 20 minute reading intervals), while rrmFtit.~tir~ preferred choices at present, ` ~ ` 2 i 80799 do not represent absolute imperative values. For that reason the wording '`about"
was resorted to in the annesed claims in respect of those p~et~.~ in order to make it clear that any possible minor changes, with respect to any of those para-meters wiU not invalidate the espected results.
Also, it is entirely possible to develop alternatives to the algorithm presentedherem that may be equally as effective. For eYample, the reading mtervals can bechosen to be more frequent or less frequent tham the 10,15 and 20 minute intervals described here. Consequently, the preferred coefficients disclosed in Tables 1 and 2 may vary ac~,~"d~&ly. The system described here provides predictions after 20 minutes for the ~Ve, le, ~ l e l~ value classically obtained using the reference method after 60 and 120 minutes. The new system clearly offers significant advantage tothe user by providing diagnostic values faster to the clinicians. By shortening the reading cycle further through the d~ lle~lt of alternative algorithms in the manner described herern or in similar manners, it would further add advantage for the clinician.
It is also entirely possible to develop algonthms with mathem- tical corrections for environmental factors encountered during the test. Such factors may include the laboratory l~ I as it is weil r ~=~liqh~l that increasing ~II~ can accelerate the g~ rate.
aiso posslble to develop algorithms w:th .,...~ l correction for patient factors affecting the blood specimen. Such factors may include the patient haemato-crit as it is well f.qfqhliqh.~ that decreasing haematocrit can accelerate the ædi-mentation rate.
,~
It is also possible to develop algorithm3 to achieve the desired correlation if one were to use specimen collection tubes of geometries and volumes or with additives other than described herein. For eYample: alternative surfact~mt; alternative citrate anticoagulant to blood ratios; alternative q n ti~q~l I qn tq such as EDTA, heparin or -` ~ 2t 80799 hirudin; alternative tube diameters, shapes or lengths. Changes to any of these factors is likely to make the algorithms described herein less optimal. However,usmg the method described herein or similar methods, new algorithms can easily be developed, without undue ~ .. being required, the key point being the recognition that the values obtained according to the invention are representa-tive - with a high degree of reliability and repeatability - of the desired ESR values.
Consequently, the values obtamed can be converted, through a given ~ ,. .,L~
(as the algorithms disclosed in the foregoing) to the classic Westergren values.
Also, it will be easily d~AV~ d that any conversion algorithm as those disclosedand/or referred to in the foregoing may be easily stored and;, ~ l (in a thoroughly known manner) in a computer such as the computer designated 11 rn figure 3 As mdicated, even though the test tube of the invention was devised for preferred use in a fully automated ESR determination method and apparatus, thoroughly satisfactory and reliable use was also ~ 1 with in a "manual" version of the ESR determination method wherein reading is s~ 1 by eye and re-quires a stand (not shown) to hold the tube vertically during a 60~120 minute reading perioa. On the stand i8 a scale read by eye in the lo~rithnnif format which converts the observed value directly to that ~ntirir~ted by the Westergren method.
The test tu~e for use in this manual version is similar .n al.l regarcls to the test tube for use rn the automated ESR (il~tPrmin~tiOn procedure described in the fore-going eYcept that a tube wall length of about 110-120 r~m, preferably about 120 mm, to yield a blood column height of nominally about 100 mm was found to be preferable. The resulting blood draw value is about 2.3 mls. The additive type, surfactant and other tube geometries are other~vise the same. As the tube is read preferably as much as 75% of the tube length, ~v~ v~vi~.~;ly shorter patient .,. data labels are usually applied at the bottom end of the tube.
Claims (23)
1. A test tube (T) for determining the erythrocyte sedimentation rate (ESR) in a blood sample, wherein said test tube includes a tubular wall defining a cavity for forming therein a column of said blood, said blood column having a given height at an initial time, whereby the location of the cell/plasma interface (I) with respect to the height of said blood column at at least one subsequent time interval is indicative of the ESR of the said blood sample, a quantity of an anticoagulation agent for the blood forming said column being provided in said cavity, characterised in that:
- said tubular wall has a length of not less than 80 mm and not more than 120 mm and an inside diameter not less than 5 mm and not more than 7 mm, and - a quantity of a surfactant is provided in said cavity for mixing to the blood forming said column, said surfactant being stable under test conditions, being capable of lowering the surface tension of whole blood, and not interfering with the haematology properties of human blood.
- said tubular wall has a length of not less than 80 mm and not more than 120 mm and an inside diameter not less than 5 mm and not more than 7 mm, and - a quantity of a surfactant is provided in said cavity for mixing to the blood forming said column, said surfactant being stable under test conditions, being capable of lowering the surface tension of whole blood, and not interfering with the haematology properties of human blood.
2. The test tube of claim 1, characterised in that said tubular wall has a length of 80 mm and an insider diameter of 6 mm.
3. The test tube of claim 1, characterized in that said tubular wall has a length of 120 mm and an inside diameter of 6 mm.
4. The tube of any of claims 1 to 3, characterised in that said tubular wall has an outside diameter of not less than 7 mm and not more than 9 mm.
5. The test tube of claim 4, characterised in that said tubular wall has an outside diameter of 8 mm.
6. The test tube of any of claims 1 to 5, characterised in that said tubular wall includes an upper portion defining a length (W) for measuring the location of said cell/plasma interface (I); said test tube having associated therewith an identification label (L) for applying onto the remaining lower part of said tubular wall.
7. The test tube of claim 6 characterised in that said upper portion (W) is 30-mm.
8. The test tube of any of claims 1 to 7, characterised in that said anti-coagulation agent includes tri-sodium citrate.
9. The test tube of any of claims 1 to 8, characterised in that said anti-coagulation agent includes citric acid.
10. The test tube of claim 8 or claim 9, characterised in that said anti-coagulation agent is a mixture of tri-sodium citrate and citric acid.
11. The test tube of any of claims 8 or 10, characterised in that said anti-coagulation agent is mixed in an aqueous solution to achieve a molarity of 0.105 M-0.135 M.
12. The test tube according to any of claims 8 or 10, characterised in that said anticoagulation agent is present in a quantity to give, in use, a blood to anti-coagulation agent ratio between 2:1 and 10:1.
13. The test tube according to any of claims 8 or 10, characterised in that said anticoagulation agent is present in a quantity to give, in use, a blood to anti-coagulation agent ratio of 4:1.
14. The test tube of claim 1, characterised in that said anticoagulation agent includes an anticoagulant selected from the group consisting of EDTA, hirudin, potassium and sodium oxalate and mixtures thereof.
15. The test tube of any of claims 1 to 14, characterized in that said quantity of surfactant is approximately 1 % by weight of the quantity of blood forming said blood column.
16. The test tube of any of claims 1 to 15, characterised in that said surfactant is non-ionic.
17. The test tube of claim 1 or claim 15, characterised in that said surfactant is an organosilicone fluid.
18. The test tube of claim 17, characterized in that said surfactant is poly-alkyleneoxide modified polydimethylsiloxane.
19. Use of a surfactant as an additive in a blood column for determining the erythrocyte sedimentation rate (ESR) of a blood sample forming said column, said surfactant being stable under test conditions, being capable of lowering the surface tension of whole blood, and not interfering with the haematology properties of human blood.
20. The use of claim 19, characterized in that said surfactant is approximately 1%
by weight of the blood forming said column.
by weight of the blood forming said column.
21. The use of any of claims 19 or 20, characterized in that said surfactant is non-ionic.
22. The use of claim 19 or claim 21, characterized in that said surfactant is an organosilicone fluid.
23. The use of claim 22, characterised in that said surfactant is polyalkyleneoxide modified polydimethylsiloxane.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP95111546.8 | 1995-07-21 | ||
| EP95111546A EP0755654B1 (en) | 1995-07-21 | 1995-07-21 | A test tube for determining the erythrocyte sedimentation rate and a surfactant for use therein |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2180799A1 CA2180799A1 (en) | 1997-01-22 |
| CA2180799C true CA2180799C (en) | 2001-03-27 |
Family
ID=8219458
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002180799A Expired - Lifetime CA2180799C (en) | 1995-07-21 | 1996-07-09 | Test tube for determining the erythrocyte sedimentation rate and a surfactant for use therein |
Country Status (7)
| Country | Link |
|---|---|
| US (1) | US5779983A (en) |
| EP (1) | EP0755654B1 (en) |
| JP (1) | JP3103308B2 (en) |
| AT (1) | ATE190820T1 (en) |
| CA (1) | CA2180799C (en) |
| DE (1) | DE69515858T2 (en) |
| ES (1) | ES2145187T3 (en) |
Families Citing this family (22)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6534016B1 (en) | 1997-04-30 | 2003-03-18 | Richmond Cohen | Additive preparation and method of use thereof |
| US6063591A (en) * | 1997-05-14 | 2000-05-16 | 3M Innovative Properties Company | System for measuring the efficacy of a sterilization cycle |
| US6025189A (en) * | 1997-05-14 | 2000-02-15 | 3M Innovative Properties Company | Apparatus for reading a plurality of biological indicators |
| DE19836559A1 (en) | 1998-08-12 | 2000-03-23 | Antigen Gmbh | Blood collection vessel |
| JP2000329779A (en) * | 1999-05-19 | 2000-11-30 | Sefa Technology Kk | Sedimentation speed measuring method and its device |
| US6196899B1 (en) * | 1999-06-21 | 2001-03-06 | Micron Technology, Inc. | Polishing apparatus |
| US20040043505A1 (en) * | 2002-05-07 | 2004-03-04 | Matthew Walenciak | Collection assembly |
| US6974701B2 (en) * | 2003-03-21 | 2005-12-13 | Hemovations, Llc | Erythrocyte sedimentation rate (ESR) test measurement instrument of unitary design and method of using the same |
| US20060216829A1 (en) * | 2003-03-21 | 2006-09-28 | Denis Bouboulis | Erythrocyte sedimentation rate (ESR) test measurement instrument of unitary design and method of using the same |
| GB0419059D0 (en) | 2004-08-26 | 2004-09-29 | Ici Plc | Sediment assessment |
| US7608457B2 (en) * | 2005-03-10 | 2009-10-27 | Streck, Inc. | Blood collection and testing improvements |
| US7419832B2 (en) * | 2005-03-10 | 2008-09-02 | Streck, Inc. | Blood collection tube with surfactant |
| EP1701148A3 (en) | 2005-03-10 | 2008-04-30 | Streck Inc. | Blood collection tube |
| DE102008052223A1 (en) * | 2008-10-17 | 2010-04-22 | Albert-Ludwigs-Universität Freiburg | Luminescence scanner for spatially resolved determination of physical characteristics of semiconductor component, has analyzing unit determining physical properties of semiconductor component from detected spatially resolved luminescence |
| WO2012018638A2 (en) | 2010-07-26 | 2012-02-09 | Biomatrica, Inc. | Compositions for stabilizing dna, rna and proteins in blood and other biological samples during shipping and storage at ambient temperatures |
| US9845489B2 (en) | 2010-07-26 | 2017-12-19 | Biomatrica, Inc. | Compositions for stabilizing DNA, RNA and proteins in saliva and other biological samples during shipping and storage at ambient temperatures |
| US9725703B2 (en) | 2012-12-20 | 2017-08-08 | Biomatrica, Inc. | Formulations and methods for stabilizing PCR reagents |
| WO2015164274A1 (en) * | 2014-04-21 | 2015-10-29 | Buglab Llc | Particle sensor with interferent discrimination |
| WO2015191632A1 (en) | 2014-06-10 | 2015-12-17 | Biomatrica, Inc. | Stabilization of thrombocytes at ambient temperatures |
| WO2017100212A1 (en) | 2015-12-08 | 2017-06-15 | Biomatrica, Inc. | Reduction of erythrocyte sedimentation rate |
| CN107693030B (en) * | 2017-11-16 | 2024-04-09 | 湖北朗泰生物科技有限公司 | Sampling test tube and sampling device |
| CN112557267B (en) * | 2020-12-25 | 2023-07-28 | 浙江师范大学 | Blood sedimentation detection device and detection method thereof |
Family Cites Families (20)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2727400A1 (en) * | 1977-06-18 | 1978-12-21 | Strahlen Umweltforsch Gmbh | METHOD OF MEASURING THE SPEED OF MOVEMENT OF A SURFACE OF A PHASE INCLUDED IN A FURTHER PHASE |
| IT1132219B (en) * | 1980-07-22 | 1986-06-25 | Luigi Prandi | COMPOSITION SUITABLE FOR SEPARATING THE EMAZIE FROM THE SERUM OR PLASMA IN BLOOD SAMPLES FOR ANALYSIS AND METHOD THAT USES THEM |
| CA1175673A (en) * | 1981-08-18 | 1984-10-09 | Robert N. O'brien | Erythrocyte settling rate meter |
| IT1192490B (en) * | 1982-08-10 | 1988-04-13 | Diesse Diagnostica Senese Srl | APPARATUS FOR THE DETERMINATION OF THE SPEED OF ERITROSEDIMENTATION OF THE BLOOD (ESR) ON A MULTIPLE OF SAMPLES |
| NO153508C (en) * | 1984-01-18 | 1986-04-02 | Ken Heimreid | QUICK METHOD FOR DETERMINING THE REDUCTION IN VENE BLOOD. |
| JPS60153843A (en) * | 1984-01-24 | 1985-08-13 | 株式会社ニツシヨ− | Blood sampling tube for examination of blood clotting |
| FR2566126B1 (en) * | 1984-06-13 | 1988-05-06 | Cinqualbre Paul | METHOD AND APPARATUS FOR AUTOMATICALLY DETERMINING, DISPLAYING AND PRINTING THE SEDIMENTATION SPEED OF SUSPENDED PARTICLES IN A BIOLOGICAL LIQUID |
| DE3529455A1 (en) * | 1984-08-24 | 1986-03-06 | Becton Dickinson GmbH, 6900 Heidelberg | Test tube for medical laboratories |
| JPH0330085Y2 (en) * | 1985-09-06 | 1991-06-26 | ||
| JPS6281056U (en) * | 1985-11-08 | 1987-05-23 | ||
| US4801428A (en) * | 1986-10-27 | 1989-01-31 | Becton, Dickinson And Company | Blood sample sedimentation test kit |
| US5065768A (en) * | 1988-09-13 | 1991-11-19 | Safe-Tec Clinical Products, Inc. | Self-sealing fluid conduit and collection device |
| US5003488A (en) * | 1989-03-10 | 1991-03-26 | Gespac, Inc. | Automatic fluid sedimentation rate measurement apparatus and method |
| IT217679Z2 (en) * | 1989-09-26 | 1992-01-16 | Diesse Diagnostica | DEVICE FOR DETERMINING THE SPEED OF ERYTHROSEDIMENTATION (VES) AND OTHER |
| US5328822A (en) * | 1990-04-23 | 1994-07-12 | Solid State Farms, Inc. | Apparatus and method for sedimentation based blood analysis |
| JP2540649B2 (en) * | 1990-04-27 | 1996-10-09 | テルモ株式会社 | Blood collection tube |
| IT1246993B (en) * | 1991-01-10 | 1994-12-12 | Diesse Diagnostica | TEST TUBE FOR BIOLOGICAL ANALYSIS EQUIPPED WITH CONTROL DEVICE, EFFICIENCY AND POSITION, FOR PHOTOMETRIC READINGS. |
| DE4117583A1 (en) * | 1991-05-29 | 1992-12-03 | Helmut Prof Dr Orth | Blood sinking measurement arrangement - compares stored position measurement values with reference curves and derives position of blood serum boundary |
| DE69220871T2 (en) * | 1991-10-03 | 1997-11-20 | Bayer Ag | Device and method for the separation and analysis of whole blood |
| US5594164A (en) * | 1994-07-12 | 1997-01-14 | Bull; Brian S. | Method and apparatus for rapid determination of blood sedimentation rate |
-
1995
- 1995-07-21 AT AT95111546T patent/ATE190820T1/en not_active IP Right Cessation
- 1995-07-21 EP EP95111546A patent/EP0755654B1/en not_active Expired - Lifetime
- 1995-07-21 DE DE69515858T patent/DE69515858T2/en not_active Expired - Lifetime
- 1995-07-21 ES ES95111546T patent/ES2145187T3/en not_active Expired - Lifetime
-
1996
- 1996-06-19 US US08/666,112 patent/US5779983A/en not_active Expired - Fee Related
- 1996-07-09 CA CA002180799A patent/CA2180799C/en not_active Expired - Lifetime
- 1996-07-22 JP JP08192565A patent/JP3103308B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| EP0755654A1 (en) | 1997-01-29 |
| JP3103308B2 (en) | 2000-10-30 |
| DE69515858T2 (en) | 2000-07-20 |
| ATE190820T1 (en) | 2000-04-15 |
| JPH09101304A (en) | 1997-04-15 |
| EP0755654B1 (en) | 2000-03-22 |
| DE69515858D1 (en) | 2000-04-27 |
| US5779983A (en) | 1998-07-14 |
| CA2180799A1 (en) | 1997-01-22 |
| ES2145187T3 (en) | 2000-07-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2180799C (en) | Test tube for determining the erythrocyte sedimentation rate and a surfactant for use therein | |
| EP0754945B1 (en) | A method and apparatus for determining the erythrocyte sedimentation rate | |
| US5914272A (en) | Test method for determining the erythrocyte sedimentation rate and a surfactant for use therein | |
| EP0830581B1 (en) | Determining erythrocyte sedimentation rate and hematocrit | |
| US4927545A (en) | Method and apparatus for automatic processing and analyzing of blood serum | |
| US5163582A (en) | Apparatus and method for aliquotting blood serum or blood plasma | |
| US4873875A (en) | System for optically interrogating liquid samples and for withdrawing selected sample portions | |
| US5555920A (en) | Method and apparatus for aliquotting blood serum or blood plasma | |
| US4066414A (en) | One piece tube and microscope slide manipulative laboratory device | |
| US20060030051A1 (en) | Erythrocyte sedimentation rate (ESR) test measurement instrument of unitary design and method of using the same | |
| EP0102764B1 (en) | Apparatus for testing sedimentation rates of liquids | |
| EP0173021B1 (en) | Process for measuring endotoxin | |
| RU2062465C1 (en) | Method and device for measuring hemoglobin content in erythrocites | |
| US4392497A (en) | Erythrocyte sedimentation rate apparatus and method | |
| Klose et al. | A rheological method for the quantification of platelet aggregation (PA) in vitro and its kinetics under defined flow conditions | |
| CA2015941A1 (en) | Method of forming agglutinates in blood samples | |
| US5322192A (en) | Pipetting apparatus | |
| CA1313516C (en) | Method and apparatus for sequential fractionation | |
| US3304784A (en) | Apparatus for measuring minute amounts of fluids | |
| CA2166914C (en) | Single sensor density measuring apparatus and method | |
| JPS5828651A (en) | Cuvette element | |
| SU1712871A1 (en) | Method for measuring biological cell diffusion rate in polycomponent solution monosystem | |
| Cooper | Interpreting lipid values in the laboratory | |
| IT8209489A1 (en) | APPARATUS FOR THE DETERMINATION OF THE SPEED OF ERYTHROSEDIMENTATION OF THE BLOOD (ESR) ON A PLURALITY OF SAMPLES | |
| Marandiuc et al. | Evaluation of the automated system DAYmate M for patient blood grouping |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKEX | Expiry |
Effective date: 20160711 |