Reliability of five rapid D-dimer assays compared to ELISA in the exclusion of deep venous thrombosis.

Studies measuring the fibrin degradation product D-Dimer (DD) using enzyme-linked immunosorbent assays (ELISA) in patients with venographically proven deep venous thrombosis (DVT) suggest that it is possible to exclude DVT when DD level is below a certain cut-off level. However, ELISA methods are time-consuming and not available in all laboratories. Different rapid latex-agglutination assays have been investigated, but their sensitivity is considerably lower. In the present study we compared the value of four novel latex DD tests (Tinaquant, Minutex, Ortho and SimpliRed) and one rapid ELISA (VIDAS) to a classical ELISA DD assay (Organon Mab Y18) in 132 patients suspected of DVT. The VIDAS, a new quantitative automated ELISA, had a sensitivity of 100% and a negative predictive value of 100% for both proximal and distal DVT at a cut-off level of 500 ng/ml. The Tinaquant assay, a new quantitative latex method, had a sensitivity of 99% and a negative predictive value of 93% for both proximal and distal DVT at a cut-off level of 500 ng/ml. For proximal DVT only, both assays had a sensitivity and negative predictive value of 100%. VIDAS and Tinaquant correlated well with ELISA (correlation of r = 0.96 and r = 0.98 respectively). Sensitivities of the semi-quantitative latex assays Minutex, Ortho and SimpliRed were considerably lower (77%, 51% and 61% respectively). These results suggest that VIDAS and Tinaquant may be used instead of ELISA DD in the exclusion of DVT. Tinaquant can be performed within 20 min and VIDAS within 35 min. Both assays might be used as a routine screening test and should be evaluated in large clinical management studies.