Accuracy of two newly described D-dimer tests in patients with suspected deep venous thrombosis.

Accumulating evidence suggests that the ELISA determination of D-Dimer might be a useful tool for the exclusion of deep vein thrombosis (DVT) of lower extremities, because of its high sensitivity and negative predictive value. However, conventional ELISA assay is time-consuming and, therefore, is not suitable for emergency use. To evaluate the accuracy of two rapid assays recently described, 126 consecutive outpatients with the clinical suspicion of DVT underwent the NycoCard D-Dimer and the Instant I.A. D-Dimer determination, using venography as the reference test. In all patients, the conventional ELISA assay was also performed. Venography confirmed the presence of DVT in 30 patients (23.8%), and ruled out the diagnosis in the remaining 96. Instant I.A D-Dimer was positive in 28 patients with DVT (sensitivity, 93.3%), and negative in 90 subjects free from thrombosis (specificity, 93.8%). Nycocard D-Dimer correctly identified 27 patients with DVT (sensitivity 90.0%), and was negative in 77 subjects free from thrombosis (specificity, 80.2%). Sensitivity, specificity, negative and positive predictive values of both tests did not differ from those found with the classic ELISA method. In conclusion, both Instant I.A. D-Dimer and Nycocard D-Dimer assays show a great potential for clinical use.