MEASUREMENT OF PROTHROMBIN FRAGMENT F1+2 FOR MONITORING THE ANTICOAGULANT EFFECT OF PHENPROCOUMON

It was the aim of this study to ascertain whether the plasma level of prothrombin fragment F1+2 is a suitable indicator of the anticoagulant effect of cumarin derivatives. The F1+2 levels were measured in 164 p atients (100 women, 64 men; mean age 63.3 [34-83] years) in whom stabl e anticoagulation had been achieved with phenprocoumon, comparing the results with those obtained in healthy subjects (28 women, 19 men; mea n age 54.6 [25-72] years) without anticoagulation. There was a signifi cant reduction (P < 0.0005) in F1+2 plasma levels with oral anticoagul ation (0.45 + 0.23 vs. 0.67 + 0.32 nmol/l). Even on a low degree of an ticoagulation (international normalized ratio [INR] < 2.0) the F1+2 va lue was reduced to within the normal range (0.32-1.2 nmol/l). These re sults indicate that changes in the plasma level of prothrombin fragmen t F1+2 are directly dependent on the degree of oral anticoagulation an d that this measure seems suitable for the monitoring of the anticoagu lant effect. This is also true for oral anticoagulation of mild degree (INR < 2.0) in which the effect cannot be satisfactorily measured by the thromboplastin time (Quick test).