Blood coagulation time test apparatus and method

• US 5,302,348 A
• Filed: 12/10/1992
• Issued: 04/12/1994
• Est. Priority Date: 12/10/1992
• Status: Expired due to Term

• Current Assignee: International Technidyne Corporation (Sphingotec GMBH)
• Original Assignee: ITC Limited
• Inventors: Samo, Robert J., Laduca, Frank M., Cusack, Robert
• Primary Examiner(s): Housel, James C.
• Assistant Examiner(s): REDDING, DAVID A
• Application Number:
  US07/988,672
• Time in Patent Office: 488 Days
• Field of Search: 422/55-59, 422/68.1, 422/73, 422/82.05, 422/82.01, 422/82.09, 422/102, 436/69, 436/165, 435/13, 73/64.41, 73/64.43, 356/39, 356/246
• US Class Current: 422/73
• CPC Class Codes: G01N 33/4905 Determining clotting time of blood by chemical methods G01N33/86, C12Q1/54
• CPC Class Codes: Y10S 436/807 Apparatus included in process claim, e.g. physical support structures

Abstract

An apparatus and method for performing a coagulation time test on a sample of blood wherein the blood is deposited in a fluid reservoir and disposable cuvette. Within the cuvette is formed a capillary conduit have at least one restricted region. The cuvette is inserted into a testing machine which engages the cuvette and draws blood from the fluid reservoir into the capillary conduit. The blood is then caused to reciprocally move within the capillary conduit whereby the blood is forced to traverse the restricted region. The testing machine measures the time required each time the blood is caused to traverse the restricted region. When a measured time is a predetermined percentage longer than an immediately preceding time, coagulation is considered to have occurred and the overall coagulation time is displayed to the operator.

Claims

1. An apparatus for performing a coagulation time test on a blood sample, comprising:

fluid reservoir for retaining the blood sample, said fluid reservoir including a volume control means for isolating a predetermined volume of the blood sample for testing;

conduit means extending from a distal end to a proximate end, wherein said distal end is coupled to said fluid reservoir, said conduit means having at least one restricted region between said distal end and said proximate end;

driving means, coupled to said proximate end of said conduit means, for selectively altering air pressure within said conduit means, said driving means controlled so as to draw the predetermined volume of the blood sample into said conduit means from said fluid reservoir and causing the predetermined volume of the blood sample to reciprocally move within said conduit means back and forth between a first position on one side of said at least one restricted region and a second position on an opposite side of said at least one restricted region;

a plurality of detection means for detecting the presence of the blood sample within said conduit means at said first position and said second position; and

control means coupled to said plurality of detection means, said control means counting the time elapsed each time the blood sample moves between said first position and said second position, said control means providing an indication to an operator when a measured time is a predetermined percentage longer than a previous measured time, whereby said predetermined percentage is indicative of coagulation in the blood sample.

2. The apparatus according to claim 1, wherein said driving means, said plurality of detection means and said control means are contained within a test device and said fluid reservoir and said conduit means are contained within a disposable cuvette that is selectively applied to said test device.

3. The apparatus according to claim 1, wherein said at least one restricted region within said conduit means has a textured surface, whereby said textured surface promotes the coagulation of the blood sample within said at least one restricted region.

4. The apparatus according to claim 1, further including a drain conduit means coupled to said fluid reservoir, said drain conduit means draining blood from said fluid reservoir after said predetermined volume of the blood sample has been drawn into said conduit means.

5. The apparatus according to claim 1, further including a heating means for heating the blood sample within said conduit means.

6. The apparatus according to claim 1, wherein said driving means includes a stepper motor controlled by said control means, said stepper motor reciprocally driving a piston within a piston cylinder to cause variations in pressure within said conduit means.

7. The apparatus according to claim 2, further including a coupling means for coupling said conduit means to said driving means when said cuvette is inserted into said test device.

8. The apparatus according to claim 2, wherein said cuvette includes a drain conduit means coupled to said fluid reservoir, said drain conduit means draining blood from said fluid reservoir after said predetermined volume of the blood sample has been drawn into said conduit means, thereby preventing blood from spilling from said fluid reservoir when said cuvette is removed from said test device.

9. The apparatus according to claim 8, wherein said test device further includes a second driving means for selectively altering the pressure within said drain conduit means, said second driving means controlled so as to draw the remnants of the blood sample into said drain conduit means that remains in said fluid reservoir after said predetermined volume of the blood sample is drawn into said conduit means.

10. The apparatus according to claim 9, further including a second coupling means for coupling said drain conduit means to said second driving means when said cuvette is inserted into said test device.

11. The apparatus according to claim 2, wherein said cuvette is formed from a translucent material and said plurality of detection means includes light sources and photoelectric sensors that detect the opaque blood within said conduit means.

12. An apparatus for performing a coagulation time test on a blood sample, comprising:

a disposable cuvette that includes;

a) fluid reservoir for retaining a predetermined volume of the blood sample within said cuvette;

b) conduit means disposed within said cuvette, extending from a distal end to a proximate end, wherein said distal end is coupled to said fluid reservoir, said conduit means having at least one restricted region between said distal end and said proximate end;

a test device including;

a) receptacle means for receiving said disposable cuvette within said test device;

b) driving means for selectively altering air pressure, said driving means interconnecting with said conduit means in said disposable cuvette as said disposable cuvette is positioned within said receptacle means, whereby said driving means is controlled to draw the blood sample into said conduit means from said fluid reservoir and cause the blood sample into to reciprocally move within said conduit means back and forth between a first position on one side of said at least one restricted region to a second position on an opposite side of said at least one restricted region;

c) a plurality of detection means for detecting the presence of the blood sample within said conduit means at said first position and said second position; and

d) control means coupled to said plurality of detection means, said control means counting the time elapsed each time the blood sample moves between said first position and said second position, said control means providing an indication when a measured time is a predetermined percentage longer than a previous measured time, whereby said predetermined percentage is indicative of coagulation in the blood sample.

13. The apparatus according to claim 12, wherein said at least one restricted region within said conduit means has a texture surface.

14. The apparatus according to claim 12, wherein said fluid reservoir includes a volume control means, said volume control means retaining any amount of the blood sample above said predetermined volume so that only said predetermined volume can be drawn into said conduit means.

15. The apparatus according to claim 12, wherein said disposable cuvette further includes a drain conduit means coupled to said fluid reservoir, said drain conduit means draining blood from said fluid reservoir after said predetermined volume of the blood sample has been drawn into said conduit means.

16. The apparatus according to claim 12, wherein said test device further includes a heating means for heating the blood sample within said conduit means.

17. The apparatus according to claim 12, wherein said driving means includes a stepper motor controlled by said control means, said stepper motor reciprocally driving a piston within a piston cylinder to cause variations in pressure.

18. The apparatus according to claim 12, wherein said disposable cuvette includes a drain conduit means coupled to said fluid reservoir, said drain conduit means draining blood from said fluid reservoir after said predetermined volume of the blood sample has been drawn into said conduit means, thereby preventing blood from spilling from said fluid reservoir when said cuvette is removed from said at test device.

19. The apparatus according to claim 18, wherein said test device further includes a second driving means for selectively altering the pressure within said drain conduit means on said disposable cuvette, said second driving means controlled so as to withdraw the remnants of the blood sample into said drain conduit means that remain in said fluid reservoir after said predetermined volume of the blood sample is drawn into said conduit means.

20. The apparatus according to claim 12, wherein said cuvette is formed from a translucent material and said plurality of detection means included light sources and photoelectric sensors that detect the opaque blood within said conduit means.

21. An apparatus for performing a coagulation time test on a blood sample, comprising:

fluid reservoir for retaining the blood sample, said fluid reservoir including a drain conduit means for draining excess amounts of the blood sample from said fluid reservoir and leaving a predetermined volume of the blood sample in said fluid reservoir for testing;

test conduit means extending from a distal end to a proximate end, wherein said distal end is coupled to said fluid reservoir, said test conduit means having at least one restricted region between said distal end and said proximate end;

driving means, coupled to said proximate end of said test conduit means, for selectively altering air pressure within said test conduit means, said driving means controlled so as to withdraw the predetermined volume of the blood sample into said test conduit means from said fluid reservoir and causing said predetermined volume of the blood sample to reciprocally move within said test conduit means back and forth between a first position on one side of said at least one restricted region and a second position on an opposite side of said at least one restricted region;

a plurality of detection means for detecting the presence of the blood sample within said test conduit means at said first position and said second position; and

control means coupled to said plurality of detection means, said control means counting the time elapsed each time the blood sample moves between said first position and said second position, said control means providing an indication when a measured time is a predetermined percentage longer than a previous measured time, whereby said predetermined percentage is indicative of coagulation in the blood sample.

22. The apparatus according to claim 21, wherein said driving means, said plurality of detection means and said control means are contained within a test device and said fluid reservoir and said conduit means are contained within a disposable cuvette that is selectively applied to said test device.

23. The apparatus according to claim 21, wherein said at least one restricted region within said test conduit means has a textured surface.

24. The apparatus according to claim 21, wherein said fluid reservoir includes a volume control means, said volume control means retaining any amount of the blood sample above said predetermined volume so that only said predetermined volume can be drawn into said test conduit means.

25. The apparatus according to claim 21, further including a heating means for heating the blood sample within said test conduit means.

26. The apparatus according to claim 21, wherein said driving means includes a stepper motor controlled by said control means, said stepper motor reciprocally driving a piston within a piston cylinder to cause variations in pressure within said test conduit means.

27. The apparatus according to claim 22, further including a coupling means for coupling said test conduit means to said driving means when said cuvette is inserted into said test devive.

28. The apparatus according to claim 21, wherein said device further includes a second driving means for selectively altering the pressure within said drain conduit means, said second driving means controlled so as to draw the remnants of the blood sample into said drain conduit means that remain in said fluid reservoir after said predetermined volume of the blood sample is drawn into said test conduit means.

29. The apparatus according to claim 28, further including a second coupling means for coupling said drain conduit means to said second driving means when said cuvette is inserted into said test device.