BLOOD COAGULATION DETECTION DEVICE

• US 3,674,012 A
• Filed: 04/17/1970
• Issued: 07/04/1972
• Est. Priority Date: 04/17/1970
• Status: Expired due to Term

• Current Assignee: Warner Lambert Limited (Pfizer Inc.)
• Original Assignee: Stanley J. Sage
• Inventors: Sage, Stanley J.
• Primary Examiner(s): Guida, Antonio F.
• Assistant Examiner(s): Heinz, H.
• Application Number:
  US05/029,563
• Time in Patent Office: 809 Days
• Field of Search: 128/2,2.1E,2.1Z,2.1R
• US Class Current: 600/369
• CPC Class Codes: G01N 33/4905 Determining clotting time of blood by chemical methods G01N33/86, C12Q1/54

Abstract

This apparatus for detecting the time of coagulation of liquid blood samples includes a hypodermic syringe having the necessary components mounted therein to perform this test. These components include a group of spatially separated electrodes which are disposed around the exterior surface of either the plunger or the base of the barrel where the cannula normally mounts to the hypodermic syringe. Means are provided for connecting the electrodes to an impedance monitoring circuit to ascertain the clotting time of the sample.

Claims

1. Apparatus for use with an impedance monitoring circuit for determining the clotting time of a blood sample, the apparatus comprising a hypodermic syringe having a barrel, a plunger, and a cannula for withdrawing and retaining the blood sample from a patient, a plurality of spatially separated electrodes attached to the syringe and engaging the blood sample, the electrodes defining a test cell and at least one control cell, said test cell being defined between a first pair of said plurality of electrodes, said control cell being defined between a second pair of said plurality of electrodes, means associated with the control cells to retard the clotting of the blood sample fraction contained therein, and means for connecting the electrodes to the impedance monitoring circuit.

2. Apparatus according to claim 1 in which the means for retarding comprises a coating of an anti-coagulating substance disposed on the surface of the control cells.

3. Apparatus according to claim 2 wherein the anti-coagulating substance is a silicone material.

4. Apparatus according to claim 2 wherein the anti-coagulating substance is a clot retarding enzyme impregnated into the surface of the control cells.

5. Apparatus according to claim 1 wherein the means for retarding comprises each of the control cells having a cross-sectional area which is greater than the cross-sectional area of the test cell.

6. Apparatus according to claim 1 wherein the plurality of spatially separated electrodes are disposed on the plunger adjacent the lower end thereof, and spaced from the interior wall of the barrel so as to define the test anD control cells therebetween.

7. Apparatus according to claim 6 in which the spatially separated electrodes are a plurality of rings of conductive material disposed around the perimeter of the plunger.

8. Apparatus according to claim 6 in which the electrodes are point contacts.

9. Apparatus according to claim 6 which further includes a common conductive bus disposed on the inner wall of the barrel.

10. Apparatus according to claim 1 in which the hypodermic syringe is disposable.

11. Apparatus according to claim 1 in which a hollow adapter is mounted between the barrel and the cannula and provides communication therebetween, the test and control cells being disposed between the barrel and the adapter.

12. Apparatus according to claim 11 in which the syringe is of the permanent type and the adapter is disposable.

13. Apparatus according to claim 11 wherein the electrodes are conductive bands disposed about the perimeter of the tip of the barrel adjacent to the base thereof.

14. Apparatus according to claim 10 wherein the electrodes are disposed in the adapter.

15. Apparatus according to claim 1 wherein one control cell is defined.

16. Apparatus according to claim 1 wherein three control cells are defined.