[Value of the determination of D-dimers in the diagnostic approach of venous thrombo-embolic disorders]. / Intérêt du dosage des D-dimères dans l'approche diagnostique des accidents thrombo-emboliques veineux.

ABSTRACT

The aim of this study is to evaluate the usefulness of plasma measurements of D-dimer using ELISA method and latex agglutination test in the diagnostic approach of venous thromboembolism. Among 126 patients suspected of pulmonary embolism (80 pat.) or deep venous thrombosis of the legs (46 pat.), the diagnosis of acute venous thromboembolism has been confirmed using gold standard invasive techniques (pulmonary angiography and/or contrast venography) in 49% of them. The sensitivity, specificity, negative predictive value and positive predictive value of a D-dimer plasma concentration above 500 ng/ml, on admission day, for the diagnosis of venous thromboembolism are 98%, 66%, 97%, 74% respectively when using the ELISA method, and 87%, 70%, 85%, 74% respectively when using the latex assay. In the 51 patients with a lung scan showing an indeterminate probability of pulmonary embolism, the sensitivity of the ELISA method is very high (94%) but that of the latex assay is low (67%). The repetition of D-dimer measurement on days 2 and 4 following admission has no significant effect on the sensitivity of the ELISA and latex assays. Our results demonstrate that the measurement of plasma D-dimer concentration using latex assay should not be used in the diagnostic approach of venous thromboembolism because the sensitivity of this test is insufficient for ruling out the presence of the disease. On the opposite, a low concentration of plasma D-dimer measured by the ELISA method might be used to rule out acute venous thromboembolism, and avoid invasive radiological techniques, especially in patients with an indeterminate probability lung scan.