FUNCTIONAL ASSAY OF PLASMA ANTITHROMBIN USING POLYETHYLENE-GLYCOL (PEG) DEFIBRINATED PLASMA

Polyethylene glycol(PEG) was used to precipitate fibrinogen to prepare defibrinated plasma in the two stage clotting assay of antithrombin a ctivity. Five percent PEG-8000 precipitated fibrinogen from plasma wit hout loss of antithrombin activity in the defibrinated plasma. Fibrin degradation products(FDP) as high as 640 ug/ml did not interfere the t wo stage clotting assay using PEG defibrinated plasma possibly because part of FDP was precipitated by PEG in the process of plasma defibrin ation. The two stage clotting assay was very sensitive to the changes of antithrombin activity in the range of 60%-100% of normal level. The assay was reproducible and correlated with chromogenic assay. The dec rease of plasma antithrombin activity in a baboon septic shock model w as demonstrated with this assay.