Comprehensive study on laboratory biomarkers for prediction and diagnosis of deep venous thrombosis.
Deep venous thrombosis (DVT) is based upon clinical suspicion in patients at risk and confirmatory duplex imaging of the deep venous system of the affected extremity. The aim of the present study was to determine different cutoff points of D-dimer, P-selectin and microparticles that could be used in early diagnosis and prediction of impending DVT in symptomatic patients with normal duplex ultrasound. Three groups of individuals were examined: 50 healthy volunteers (Group I); 75 patients with positive duplex ultrasound for DVT (Group II) and 75 symptomatic patients, but with negative duplex ultrasound for DVT (Group III). D-dimer was measured by immunoturbidimetric assay, P-selectin by flow cytometry and microparticles by ELISA. D-dimer, P-selectin and microparticles levels were significantly higher in Group II and III patients when compared with Group I individuals. Using receiver-operating characteristic curves, we determined that cutoff levels of 0.92 mg/l for D-dimer, 17.8% for P-selectin and 16.5 nmol/l for microparticles can accurately rule out DVT. New cutoff levels were estimated for the three studied biomarkers that differentiated the group of DVT-negative duplex patients without thrombosis from those patients of the same group who developed thrombosis being 2.81 mg/l for D-dimer, 30.2% for P-selectin and 26 nmol/l for microparticles. D-dimer, P-selectin and microparticles can be used to diagnose and detect impending DVT, thus identifying patients at high risk that could benefit from early anticoagulant therapy without the need for imaging studies.