Comparison of three D-dimer assays for the diagnosis of DVT:ELISA, latex and an immunofiltration assay (NycoCard D-Dimer).

Ninety-two consecutive patients referred for suspicion of deep venous thrombosis (DVT) were analyzed for D-dimer using ELISA, latex test, and a new immunofiltration method (NycoCard D-Dimer). Contrast venography verified the diagnosis in 40, and excluded the diagnosis in 52 patients. The sensitivity, negative predictive values, specificity and positive predictive values were, for ELISA 98%, 95%, 38% and 54, for NycoCard D-Dimer 100%, 100%, 42% and 57% and for the latex test 73%, 78%, 75%, and 69%, respectively. Sensitivity and specificity were inversely related with increasing pathological cut-off value. Comparison of test results by concentration category revealed a good agreement between ELISA and NycoCard D-Dimer, but to less extent between latex and the two other tests. It is concluded that NycoCard D-Dimer and D-dimer ELISA are well-suited as exclusion tests for DVT. A plasma sample is tested with NycoCard D-Dimer in less than 2 min. Thus, this test combines advantageous analytical properties comparable to the ELISA-test, with rapidity and simplicity comparable to the latex test.