Three different assays for fïbrin/fibrinogen degradation products (FDP) were evaluated in patients with suspected pulmonary embolism (PE) as rapid screening tests with the aim of evaluating whether they could be used either as a substitute of ventilation/perfusion lung scanning or to supplement scintigraphy in patients in whom the scan was inconclusive (low or intermediate probability). D-Dimer by enzyme-linked immunosorbent assay (ELISA) and latex and total FDP by ELISA were measured prospectively in 85 consecutive patients with suspected PE. With a cutoff of 500 ng/ml, D-dimer by ELISA presented a 96% sensitivity and a 42% specificity, with positive and negative predictive values of 49 and 96%, respectively. D-Dimer by latex, also with a cutoff of 500 ng/ml showed a 93% sensitivity and 29% specificity, with positive and negative predictive values of 43 and 89%. For total FDP, with a cutoff of 900 ng/ml, the sensitivity and specificity were 96 and 26% respectively, with positive and negative predictive values of 42 and 93%. A normal assay may have reduced the necessity of a ventilation/perfusion only in 28% patients with D-dimer ELISA, 21% with D-dimer latex and 17% with total FDP ELISA and with a possible error of 4, 11 and 7%, respectively. Conclusions: (1) a D-dimer by ELISA < 500 ng/ml or total FDP by ELISA < 900 ng/ml excludes the diagnosis of PE, and no more studies are needed; (2) a D 900 ng/ml does not exclude other diagnostic procedures, and (3) more extensive studies are needed to clarify the utility of D-dimer by latex