The relatively new D-dimer assay from Nycomed Pharma (Nycocard), which has shown both high sensitivity and specificity in diagnosing deep venous thrombosis (DVT) and pulmonary embolism (PE) in earlier studies, was re-evaluated retrospectively. The diagnostic value of the D-dimer assay for DVT was evaluated with contrast venography as reference. The diagnostic value of the D-dimer assay for PE was evaluated with pulmonary scintigraphy as reference. D-dimer tests were examined from 54 consecutive patients. The D-dimer assay was found to have a sensitivity and specificity of 50% and 58%, respectively, for the diagnosis of DVT, with a positive predictive value (PPV) and negative predictive value (NPV) of 55% and 54%, respectively. Using reference diagnostic results of high probability and low probability for the diagnosis of PE, the D-dimer test sensitivity and specificity was found to be 40% and 94%, respectively (PPV: 86%, NPV: 64%). The diagnostic value of the Nycocard(R) assay appears to be very limited for the diagnosis of DVT and PE. This retrospective study suggests that it is unsuitable as a screening method. Further re-evaluation of D-dimer assays is recommended prior to routine clinical use.