THE ROUTINE DETERMINATION OF THE ENDOGENOUS THROMBIN POTENTIAL, FIRSTRESULTS IN DIFFERENT FORMS OF HYPERCOAGULABILITY AND HYPOCOAGULABILITY

The area under the thrombin generation curve (the endogenous thrombin potential; ETP) has been proposed as a parameter for plasma-based hype rcoagulability and to monitor anticoagulant treatment. We present an E TP assay for the routine laboratory using a centrifugal analyser. Thro ughput is 30 samples/h, within and between run imprecision is 4-5.6%. Suitable substrates were developed for the ranges of 10-500% and 2-100 % of normal. Independent of tissue factor concentration (if >4 pM), th e normal value of the extrinsic ETP is 384.8 +/- 51.7 nM.min. The intr insic ETP, triggered by ellagic acid, is 414 +/- 41 nM.min. The ETP is decreased to 15 and 35% of normal by oral anticoagulation (INR 2.5-4. 0) and by heparin administration (APTT 1.5-2.5 X control). The ETP is increased in untreated subjects with congenital antithrombin deficienc y and in women using oral contraceptives. In deep vein thrombosis (phl ebographically confirmed), it is increased by 29.4% (extrinsic) and 53 % (intrinsic). In (angiographically assessed) coronary artery disease the increase is by 10% and 17% respectively.