title: Antithrombin-III assay without influence of heparin cofactor II.
abstract: A new biological method for the assay of plasma antithrombin-III (AT-III) activity was developed without influence from heparin cofactor II (HC-II). AT-III deficient plasma is used as a substrate and diluted prothrombin time reagent as a reaction trigger for the specific assay of AT-III. The AT-III deficient plasma is prepared by passage of plasma through a heparin-agarose column. In the presence of heparin, AT-III in the sample shows concentration dependent anticoagulant activity and calibration curve is linear on semi-logarithmic graph paper. The results of reproducibility, recoveries and correlation studies with a chromogenic assay indicate that this biological method is reliable and suitable for routine use in clinical laboratories. Influence of HC-II is minimal. The method provides several advantages over those of chromogenic substrate and fibrinogen.
authors.affiliation: Research Laboratories, Nippon Shoji Kaisha, Ltd., Osaka, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Enomoto
authors.forename: I
authors.initials: I
authors.lastname: Tanimizu
authors.forename: N
authors.initials: N
authors.lastname: Sakuragawa
mesh_terms: D000990:Antithrombin III / Q000032:analysis*; D001780:Blood Coagulation Tests; D002846:Chromatography, Affinity; D002863:Chromogenic Compounds; D005170:Factor X / Q000037:antagonists & inhibitors; D015844:Heparin Cofactor II; D006801:Humans; D012685:Sepharose / Q000031:analogs & derivatives; D013917:Thrombin / Q000037:antagonists & inhibitors
chemical_list: D002863:Chromogenic Compounds; C037405:heparin-sepharose; D015844:Heparin Cofactor II; D000990:Antithrombin III; D005170:Factor X; D012685:Sepharose; D013917:Thrombin