Method for prothrombin testing

• US 3,918,908 A
• Filed: 05/17/1974
• Issued: 11/11/1975
• Est. Priority Date: 05/17/1974
• Status: Expired due to Term

• Current Assignee: Donald J. Sibbett, Rudolph H. Moyer
• Original Assignee: Donald J. Sibbett, Rudolph H. Moyer
• Inventors: Moyer, Rudolph H., Sibbett, Donald J.
• Primary Examiner(s): Wolk, Morris O.
• Assistant Examiner(s): Hagan, Timothy W.
• Application Number:
  US05/470,894
• Time in Patent Office: 543 Days
• Field of Search: 23/23B,253R,259,292 73/57,64.1 128/2G,2M,DIG.22
• US Class Current: 436/69
• CPC Class Codes: G01N 11/02 by measuring flow of the material
• CPC Class Codes: Y10S 128/22 Blood coagulation

Abstract

A method, useful for the rapid measurement of coagulation rates, employing a uniform bore reaction tube which may be used to take up the sample and contains the appropriate amounts of lyophilized reagents required to conduct individual tests such as that for prothrombin time. In the example disclosed, calibration marks on the tube have been correlated in terms of prothrombin times. The position at which a liquid sample becomes immobilized as it descends down the tube corresponds to the test time. The rate of descent is controlled by a limiting orifice or by inclining the tube to the vertical axis.

Claims

1. METHOD OF REPRODUCIBLY MEASURING CHANGES OF VISCOSITY IN A LIQUID SAMPLE SUBJECT TO AN ENCREASE IN VISCOSITY AFTER COMBINATION WITH AT LEAST ONE REAGENT CAPABLE OF ALTERING SAID SAMPLE VISCOSITY COMPRISING:

A. INJECTING SAID SAMPLE INTO A HOLLOW CYLINDER HAVING AN INTERNAL DIAMETER SUFFICIENTLY LARGE SO AS TO SUBSTANTIALLY ELIMINATE EFFECTS OF INITIAL SAMPLE VISCOSITY SAID INJECTING STEP INCLUDING COMBINING SAID SAMPLE WITH AT LEAST ONE SAID REAGENT, B. PASSING SAID SAMPLE AND REAGENT COMBINATION IN SAID CYLINDER BY SUPPORTING SAID CYLINDER IN SUCH A MANNER THAT

2. The method of claim 1 in which the rate of descent of said sample is controlled.

3. The method of claim 2 in which said control is accomplished by inclining the cylinder to various angles from the vertical.

4. The method of claim 2 in which said control is accomplished by a limiting orifice.

5. The method of claim 2 in which said control is accomplished by a porous solid material.

6. The method of claim 1 in which the interior surface of the cylinder is uniformly wettable by the sample.

7. The method of claim 1 wherein said combining step comprises contacting said injected liquid sample with a reagent at a specified position within said hollow cylinder.

8. The method of claim 7 in which the chemical reagent is immediately below a calibration mark indicating the volume of sample with which the cylinder has been previously injected.

9. The method of claim 7 in which the chemical reagent is lyophilized.

10. The method of claim 7 in which the chemical reagent is in the form of a reagent plug.

11. The method of claim 1 in which said reagent is pre-mixed with said liquid sample in said injecting step.

12. The method of claim 1 in which the chemical reagent comprises thromboplastin reagents and additives in quantities sufficient to cause a prothrombin reaction when dissolved in a liquid sample of whole Blood or plasma.

13. The method of claim 1 in which the sample comprises said reagents capable of altering the viscosity of said sample upon placement within the cylinder.

14. Method of reproducibly measuring coagulation rates of fluid samples comprising:

A. injecting said fluid sample into a hollow cylinder of uniform bore of a diameter sufficiently large so as to substantially eliminaate effects of sample viscosity, and containing therein lyophilized reagents reactable with said fluid sample;

B. passing said sample in said cylinder by supporting said cylinder in a manner such that gravity causes said sample to move in a downward direction thus contacting said lyophilized reagents;

C. gauging the movement of said sample as it descends down from said contact with said reagents until it reaches a position of substantial immobilization.

15. The method of claim 14 in which the lyophilized reagents comprise thromboplastin and calcium and the fluid sample comprises whole blood or plasma.