Prothrombin time after heparin removal. Application to monitoring simultaneous anticoagulation with heparin and coumarins.

Coumarin-anticoagulated plasmas from 31 subjects comprising two study groups were passed through epichlorohydrin triethanolamine cellulose (ECTEOLA) chromatography columns. Group I plasmas, which were run with nothing added, had mean prothrombin times of 21.6 +/- 5.4 sec prior to and 22.4 +/- 5.6 sec following exposure to these columns (r = 0.9449; t = 1.8307, P less than 0.100). The mean prothrombin time for Group II, 18.2 +/- 4.9 sec, lengthened with 5 u/ml heparin to 35.5 +/- 16.2 sec, and returned to 19.2 +/- 5.0 (r = 0.9763) after chromatography. Therefore, it appears that coumarin anticoagulation had no significant influence upon the capacity of ECTEOLA effectively to remove heparin in therapeutic doses. This means that virtually all prothrombin time reagent systems can be employed to monitor concurrent heparin and coumarin anticoagulation. In addition, quality control of the combined technic is simpler, and the technic more sensitive to low levels of fibrinogen and factor V.