Plasma D-dimer measurement in patients with suspected DVT - a means of avoiding unnecessary venography

Objectives: To assess the applicability of plasma D-dimer levels in the exclusion of a DVT. Design: Consecutive cohort of patients. Materials and Methods: Eighty consecutive patients presenting to the radiology department with a clinical diagnosis of DVT were included. Citrated blood samples were taken from all patients before radiological investigation, plasma isolated and frozen for subsequent testing. The patients then underwent venography (duplex scan was also used in some cases). Plasma samples were tested using the NycoCard D-Dimer. NycoCard Reader was used to estimate the D-dimer concentrations. Results: A DVT was diagnosed in 29 cases (36.7%). Plasma D-dimer levels had a sensitivity of 96% (only one false negative), specificity of 40%, positive predictive value of 48%, and negative predictive value of 95% when compared to venography. Conclusions: A normal plasma D-dimer level could be used as an exclusion test for DVT avoiding complications of venography and saving time and money.