A laboratory method for determination of overall haemostatic potential in plasma. I. Method design and preliminary results.

The aim of this study was to design a simple laboratory method that can screen the overall haemostatic potential in plasma (OHPP) when a hyper- or hypocoagulable state is present. A fibrin time curve was made via spectrophotometric registration of fibrin generation and lysis in plasma, to which exogenous thrombin and tissue type plasminogen activator was added. The area under the curve, calculated by the sum of absorbance (ABS-sum), varied in correlation to the concentrations of platelets or purified pro-/anticoagulants: tissue factor, von Willebrand factor, fibrinogen, antithrombin, plasminogen, or plasminogen activator inhibitor type 1. The ABS-sums also changed in positive relation to the haemostatic function investigated in 16 menopausal women and 14 young healthy nonpregnant women (controls). The findings imply that the ABS-sums not only offer a general information about fibrin generation and lysis in vitro, but also reflect the OHPP (i.e., final combined effects of platelet activity, coagulation, and fibrinolysis in vivo). Preliminary results were satisfactory; the levels of OHPP, expressed as the ABS-sums, were higher in normal pregnant women than in the controls, and even higher in preeclamptic patients than in pregnant women with no complications, which corresponds to the different grades of hypercoagulability in the three groups. Moreover, the level of OHPP was considerably lower in an untreated infant with von Willebrand's disease type 3 and in factor VIII- or factor IX-deficient plasma samples.