title: Determination of prothrombin by a micro-coagulation method.
abstract: In contrast to earlier assays, the prothrombin determination described here uses a two-step reaction: first, prothrombin is activated with human factor Xa, phospholipids, Ca++ and factor V; second, the amount of activated prothrombin is assayed by the proteolysis of added fibrinogen. The assay is dependent only on prothrombin, and independent of other components of thrombin generation. Carboxy- and decarboxyprothrombin can be differentiated by means of using Echis carinatus venom instead of factor Xa as activator. The micro-coagulation assay is compared with a conventional one-stage coagulation test, with a prothrombin determination using chromogenic substrate and immunologically by Laurell electrophoresis.
mesh_terms: D002118:Calcium / Q000032:analysis; D002863:Chromogenic Compounds; D005165:Factor V / Q000032:analysis; D005170:Factor X / Q000032:analysis; D015951:Factor Xa; D005340:Fibrinogen / Q000032:analysis; D006801:Humans; D008832:Microchemistry / Q000379:methods*; D010714:Phosphatidylethanolamines / Q000032:analysis; D011516:Prothrombin / Q000032:analysis*; D011517:Prothrombin Time
chemical_list: D002863:Chromogenic Compounds; D010714:Phosphatidylethanolamines; D005165:Factor V; D011516:Prothrombin; D005170:Factor X; D005340:Fibrinogen; D015951:Factor Xa; D002118:Calcium