Clinical evaluation of an immunoturbidimetric D-dimer assay in the diagnostic procedure of deep vein thrombosis and pulmonary embolism.

We investigated 128 patients with suspected deep vein thrombosis and 26 patients with suspected pulmonary embolism. Plasma cross-linked fibrin degradation products were measured instantly by a new rapid and fully quantitative immunoturbidimetric assay (Boehringer Mannheim) which recognizes the D-dimer epitope by antibody-coated latex particles. Diagnosis of deep vein thrombosis was established by either ascending venography (n = 105) or colour duplex ultrasound (n = 8), whereas for the exclusion of deep vein thrombosis only venography was accepted. The sensitivity/specificity for the diagnosis of deep vein thrombosis was 98%/44%. Patients with suspected pulmonary embolism were examined by pulmonary angiography (n = 19) or perfusion lung scanning alone (n = 6), if sufficient. One pulmonary embolism was diagnosed at post-mortem examination. For pulmonary embolism, sensitivity/specificity was 100%/50%. These findings indicate that the new immunoturbidimetric technique is as reliable as former ELISA methods and allows to rule out thromboembolic disorders. D-dimers showed a correlation to the extent of the deep vein thrombosis, proximal thrombosis producing higher D-dimer levels. Patients presenting immediately after the onset of symptoms were found to have higher D-dimers than patients examined after a few days. A quantitative D-dimer measurement thus seems to provide precious additional information of the duration and the extent of thromboembolic disease.