Composition, kit and method for assaying heparin and a method for making the composition

• US 4,946,775 A
• Filed: 06/09/1989
• Issued: 08/07/1990
• Est. Priority Date: 09/05/1985
• Status: Expired due to Fees

• Current Assignee: Yin E. Thye
• Original Assignee: Yin E. Thye
• Inventors: Yin, E. Thye
• Primary Examiner(s): Hill, Jr., Robert J.
• Application Number:
  US07/363,783
• Time in Patent Office: 424 Days
• Field of Search: 436/69, 436/93, 436/94, 436/111, 436/119, 436/127, 436/128, 436/129, 436/131, 436/166, 435/13, 422/61
• US Class Current: 435/13
• CPC Class Codes: C12Q 1/56 involving blood clotting factors, e.g. involving thrombin, thromboplastin, fibrinogen
• CPC Class Codes: G01N 2333/96444 Factor X (3.4.21.6)
• CPC Class Codes: G01N 2400/40 Glycosaminoglycans, i.e. GAG or mucopolysaccharides, e.g. chondroitin sulfate, dermatan sulfate, hyaluronic acid, heparin, heparan sulfate, and related sulfated polysaccharides
• CPC Class Codes: G01N 2405/04 Phospholipids, i.e. phosphoglycerides
• CPC Class Codes: G01N 33/86 involving blood coagulating time or factors, or their receptors
• CPC Class Codes: Y10T 436/143333 Saccharide [e.g., DNA, etc.]

Abstract

A composition, kit and method for determining the concentration of heparin in a blood plasma sample and a method for making the composition. The method includes incubating a blood plasma sample with a known amount of Factor X_a, combining the incubated product with an admixture of calcium chloride, brain phospholipids, and a buffered plasma fraction that has been produced by treating mammalian blood to substantially remove Factors II, VII, IX and X while retaining Factor V and fibrinogen, and measuring the time it takes for clotting to occur after combining the incubated product with the admixture.

Claims

1. A method for determining the concentration of heparin in a blood plasma sample which comprises

(A) incubating the blood plasma sample for a limited period of time with a known amount of Factor X_a, to form an incubated product which known amount is in excess of the amount needed to react with all heparin - AT III complexes in the blood plasma sample within a given time period,

(B) combining the incubated product of step (A) with an admixture of

(1) calcium chloride,

(2) brain phospholipids, and

(3) a buffered plasma fraction that has been produced by treating mammalian blood to substantially remove clotting Factors II, VII, IX and X while retaining clotting Factor V and fibrinogen,

said admixture being characterized by the fact that

(a) it does not clot by itself for at least 24 hours at 37°

C., and

(b) it forms a firm clot in the presence of added thrombin, and

(c) it contains at least 50% of Factor V that is present in one ml of normal human plasma, and

(d) it provides a linear heparin dilution curve using a standard heparin preparation, and

(C) measuring the time it takes for clotting to occur after combining the incubated product of step (A) with said admixture, which clotting time is directly proportional to the concentration of heparin present in the blood plasma sample.

2. An assay composition comprising an admixture of

(1) calcium chloride,

(2) brain phospholipids, and

(3) a buffered plasma fraction that has been produced by treating mammalian blood to substantially remove clotting Factors II, VII, IX and X while retaining clotting Factor V and fibrinogen,

said admixture being characterized by the fact that

(a) it does not clot by itself for at least 24 hours at 37°

C., and

(b) it forms a firm clot in the presence of added thrombin, and

(c) it contains at least 50% of Factor V that is present in one ml of normal human plasma, and

(d) it provides a linear heparin dilution curve using a standard heparin preparation.

3. A kit for determining the amount of heparin in a selected blood plasma sample which comprises

(A) a container of a first reagent which comprises Factor X_a, the amount of the Factor X_a being in excess of the amount needed to react with all heparin - AT III complexes in the selected blood sample within a given time period,

(B) a container of a second reagent which comprises an admixture of

(1) calcium chloride,

(2) brain phospholipids, and

(3) a buffered plasma fraction that has been produced by treating mammalian blood to substantially remove clotting Factors II, VII, IX and X while retaining clotting Factor V and fibrinogen,

said admixture being characterized by the fact that

(a) it does not clot by itself for at least 24 hours at 37°

C., and

(b) it forms a firm clot in the presence of added thrombin, and

(c) it contains at least 50% of Factor V that is present in one ml of normal human plasma, and

(d) it provides a linear heparin dilution curve using a standard heparin preparation.

4. A method for producing an assay composition comprising

(a) treating a cell-free mammalian blood plasma to remove Factors II, VII, IX and X and recovering a clear plasma supernatant,

(b) subjecting said clear plasma supernatant to a protein fractionation treatment and recovering a protein fraction that contains fibrinogen and Factor V,

(c) subjecting the protein fraction of step (b) to a purification treatment to remove therefrom any soluble ammonium salt and insoluble proteins, and obtaining a clear plasma fraction,

(d) buffering said clear plasma fraction to obtain a buffered plasma fraction,

(e) admixing said buffered plasma fraction with calcium chloride and brain phospholipids, and recovering an admixture that is characterized by the fact that

(1) it does not clot by itself for at least 24 hours at 37°

C., and

(2) it forms a firm clot in the presence of added thrombin, and

(3) it contains at least 50% of Factor V that is present in one ml of normal human plasma, and

(3) it provides a linear heparin dilution curve using a standard heparin preparation.