D-dimer for the exclusion of venous thromboembolism: comparison of a new automated latex particle immunoassay (MDA D-dimer) with an established enzyme-linked fluorescent assay (VIDAS D-dimer)

The use of D-dimer tests to exclude venous thromboembolism is an important advance in clinical practice and also has economic benefits. Ideally the te st should be objective and a test that could be run on the routine coagulom eter would obviate the need for additional investment in alternative hardwa re. A new automated latex particle immunoassay (MDA D-dimer) that can be ru n on a routine coagulometer was compared with a well established enzyme lin ked fluorescent assay (VIDAS D-dimer) on the basis of their ability to excl ude venous thromboembolism. The assays were compared in 49 patients present ing to the emergency department with clinically suspected deep vein thrombo sis or pulmonary embolism. After objective diagnostic imaging, 20 patients were confirmed to have venous thromboembolism. There was strong agreement b etween the assays in individual patients. Using a cut-off of 500 mu g/l, bo th tests had a sensitivity of 100% and therefore a negative predictive valu e of 100%, however the MDA test would have spared more patients (20% vs. 12 %) from further testing if a negative D-dimer was used to rule-out the diag nosis. It was concluded that a rapid, objective latex D-dimer test run on a routine coagulometer (MDA D-dimer) can be used to exclude the diagnosis of venous thromboembolism.