Diagnostic value of a new sensitive membrane based technique for instantaneous D-dimer evaluation in patients with clinically suspected deep venous thrombosis.

Abstract : BACKGROUND: Plasma D-Dimer analysis, using ELISA assays, has demonstrated in previous studies a high sensitivity, suggesting its utility in excluding deep venous thrombosis (DVT). Aim: To assess the performance of a new rapid plasma D-Dimer ELISA measurement in suspected DVT patients with recent clinical signs, not exceeding one week. METHODS: A prospective study of patients admitted for a suspected recent DVT. Contrast venography or compression ultrasonography were performed within 24 h of admission. A new membrane based ELISA technique, which uses an immunofiltration and two complementary monoclonal antibodies was tested. Results were expressed as positive or negative. A standard plasma D-Dimer ELISA measurement was also performed. D-Dimer performances were assessed at the end of the study. RESULTS: 265/448 patients had a proven DVT (72 distal, 193 proximal). The sensitivity of the instantaneous method in the diagnosis of overall DVT is 92 +/- 3.4% (95% CI), and specificity is 36.6 +/- 6.9%. Positive predictive value is 67.7 +/- 4.8% and negative predictive value is 76.1 +/- 8.9%. Sensitivity and negative predictive values reach 97.9 and 94.3% in the diagnosis of proximal DVT, but only 76.3 and 79.7% in the diagnosis of distal DVT. Similar results are observed with the standard ELISA method. CONCLUSION: This new rapid plasma D-Dimer measurement appears highly sensitive, and could substitute the older ELISA methods. Both methods provide lower sensitivity in the case of a distal DVT location.