Comparison of prothrombin fragment 1+2 with thrombin-antithrombin III complex in plasma of patients with disseminated intravascular coagulation

Plasma levels of prothrombin fragment 1 + 2 (F1 + 2) and thrombin-antithrombin III complex (TAT) are thought to be specific indicators of thrombin generation. To assess whether these two parameters behave similarly in vivo, we compared the plasma levels of F1 + 2 with TAT in 41 patients with disseminated intravascular coagulation (DIC). Both F1 + 2 and TAT were markedly elevated in patients with DIC compared to healthy subjects. Although a positive correlation was found between F1 + 2 and TAT (r = 0.585, P < 0.001) there was a large scatter among individuals. In addition, plasma concentrations of TAT were much lower than F1 + 2. The correlation between the TAT/F1 + 2 ratio and antithrombin III was weak (r = -0.268, P = 0.09). The TAT/F1 + 2 ratio was positively correlated with TAT (r = 0.481, P = 0.002), indicating that the difference in molar concentrations between F1 + 2 and TAT decreased as the TAT value increased. Serial determinations of these parameters showed that plasma TAT values changed roughly in parallel with F1 + 2 in the majority of patients. Although further studies are required to further clarify the observed differences between F1 + 2 and TAT, both parameters would be equally useful for the precise detection of haemostatic activation in patients with DIC.