174-POS

Objectives Venous thromboembolism (VTE) remains a leading cause of maternal mortality. An effective predictive test would be very clinically important. Measurements of Calibrated Automated Thrombogram (CAT) parameters in the presence and absence of thrombomodulin have been correlated with risk of recurrent VTE. D-Dimers and soluble P-selectin are markers of thrombosis. We aimed to evaluate the CAT assay, D-Dimers and P-selectin as potential predictive tools for thrombosis in pregnancy. Methods The SCOPE (Screening for Pregnancy Endpoints) study is a prospective, multicentre cohort study of nulliparous women with the primary aim of developing screening tests to predict pre-eclampsia, small for gestational age infants and spontaneous preterm birth. Twenty patients with documented VTE in pregnancy or postpartum and 61 controls were identified from the SCOPE cohort (total of 5000 pregnant women). The control group was matched for age, gestation, BMI and ethnicity. CAT assay with and without presence of thrombomodulin was performed on citrated plasma collected at 15 weeks gestation, prior to any thrombotic event. Normalised thrombomodulin sensitivity ratios (n-TMsr) were calculated. D-dimers and P-selectin were also measured by ELISA. Results There were no significant difference in ETP, peak thrombin, lagtime , time to peak, n-TMsr, D-dimer or P-selectin levels between patients who subsequently developed VTE compared with those who remained thrombosis free. Standardisation of CAT assay is needed to ensure it is a clinically effective predictive tool. Conclusions CAT assay, D-dimer and P-selectin levels are not useful as predictors of VTE in a low risk population of primigravida screened at 15 weeks. Disclosures S.K. Ismail: None. L. Norris: None. A. Khashan: None. N. Simpson: None. G. Dekker: None. J. Myers: None. L. McCowan: None. L. Kenny: None. J.R. Higgins: None.