The performance of a new membrane ELISA for semi-quantitative determination of plasma D-dimer has been evaluated. Its cut-off is about 500 ng/ml FEU and this single test is completed within 10 min. D-dimer was measured in 301 patients suspected of pulmonary embolism by conventional microplate and membrane ELISA. For the latter, readings were made by eye and some differences were noticed between the readers for reactions in the grey zone. Sensitivity and negative predictive values were similar for the two ELISA (higher than 90%). The 95% confidence intervals of sensitivity and negative predictive values obtained with this membrane ELISA suggest that this new test may be used as a diagnostic tool to exclude the presence of pulmonary embolism.