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

Claim 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.

Claim 2

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.

Claim 7

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.

Claim 8

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.