A rapid activated protein C sensitivity test as a diagnostic marker for a suspected venous thromboembolism in pregnancy and puerperium

Objective: The purpose of the study was to examine whether changes in response to activated protein C (APC) can be a diagnostic marker of venous thromboembolism (VTE) during pregnancy and puerperium. Methods: The normalized APC sensitivity ratio (sr) was examined in arbitrarily selected healthy Japanese pregnant females and compared with those in non-pregnant females and patients with VTE at the onset before anticoagulation in pregnancy and puerperium using an endogenous thrombin potential-based assay with a computer-assisted calibrated automated thrombography. Results:Sensitivity to APC in patients with VTE at onset was reduced in comparison to that in late pregnancy period and puerperium (p < 0.01, Student's t test). The odds ratio for VTE was 31.9 with statistical significance in pregnant females with suspected clinical symptoms and APC-sr (≥5), although the odds ratio for VTE was not significant with D-dimer (≥5). Conclusion: These data suggest that an APC sensitivity test can be a possible surrogate diagnostic marker of suspected VTE during pregnancy and puerperium.