Qualitative D-Dimer in deep vein thrombosis: A single center prospective study from Kashmir India

Objective: The aim of our study was to study the significance of qualitative D-dimer in the diagnosis of deep vein thrombosis. Study Design: Prospective analysis. Setting: Tertiary care hospital. Materials and Methods: One hundred and twenty nine patients of suspected deep vein thrombosis were included in the study and further categorized as likely or unlikely to have deep vein thrombosis on Wells scoring system. The patients in both the likely and unlikely categories were then randomly assigned to undergo D-dimer testing (D-dimer group) or to undergo ultrasound imaging alone (control group). The patients with pre text clinical probability score as unlikely and with negative D-dimer test were considered not to have DVT. The primary event was recurrent venous thromboembolism in both the groups during three months of follow-up. Results: A total of one hundred and twenty nine patients with suspected DVT were included in the study. Sixty five patients were randomly assigned to D-dimer group and sixty four to the doppler group. The diagnosis of DVT was established in 41 (31.78%) patients. Among patients in whom DVT was ruled out by the initial diagnostic evaluation one case of deep vein thrombosis was confirmed in the D-dimer group (1/55, 1.8%; 95% confidence interval, 1.6 to 5.2%) and two cases in the Doppler group (2/51, 3.92%; 95% confidence interval, 1.5 to 9.34%) during three months of follow-up. The use of D-dimer resulted in lesser number of USG (0.66 tests per person) in the D-dimer group as compared to (1.23 tests per person) in the Doppler group. Forty patients (31%) in the D-dimer group did not require ultrasound imaging. Conclusion: The diagnostic performance of qualitative D-dimer assay combined with a clinical pre text probability score can also rule out DVT safely in low probability scores without significantly compromising safety.