Background: Tissue factor (TF) is involved in tumor growth and metastasis and contributes to venous thromboembolism( VTE) in cancer, including gynecological malignancies. The diagnostic value of microvesicle-associated TF procoagulant activity (MV TF PCA) in women with suspected ovarian cancer, however, has not been studied. Objective: To evaluate MVTF PCA as a diagnostic tool in women with an ovarian mass of unknown etiology and as a predictive biomarker for perioperative VTE. Methods: Plasma MVs were isolated by high-speed centrifugation and analyzed for TF-specific PCA by single-stage clotting assay. In addition, plasma TF antigen and soluble P-selectin (sCD62P) were measured by ELISA. Results: D-Dimer, MVTF PCA, and sCD62P, but not the tumor marker, CA-125, significantly differentiated patients with malignant (n = 40) from those with benign tumors (n = 15) and healthy controls (n = 34). In cancer patients, only D-Dimer and CA-125 correlated with the FIGO stage. An abnormal D-dimer had the highest sensitivity for the diagnosis of cancer, while MV TF PCA above the ROC curve-derived cut-off value of 182 U/mL had the highest specificity. By multivariate logistic regression analysis, addition of MV TF PCA conferred diagnostic benefit to the single variables, CA-125 (p = 0.052) and D-dimer (p = 0.019). Perioperative VTE occurred in 16% of cancer patients and was associated with an advanced FIGO stage, but not MV TF PCA. There was no difference in plasma TF antigen levels between study groups. Conclusions: MV TF PCA, but not plasma TF antigen, may provide valuable additional information for the diagnostic work-up of women with suspected ovarian cancer. (C) 2016 Elsevier Ltd. All rights reserved.