D-dimers in the diagnosis of pulmonary embolism

The aim of this study was to determine if the absence of circulating D-dime rs, as determined by latex agglutination assays, can correctly exclude the presence of pulmonary embolism using pulmonary angiography as the diagnosti c endpoint. Blood samples were obtained prospectively at the time of angiog raphy for suspicion of acute pulmonary embolism. Plasma was assayed for D-d imer by five different latex agglutination assays. Angiographic evidence of pulmonary emboli was found in 34% (35/103) of patients. The latex agglutin ation assays had sensitivities of 97 to 100% and specificities of 19 to 29% . The negative predictive value was 94 to 100%. However, a negative D-dimer was rare in patients with recent surgery, malignancy, or total bilirubin > 34 mu mol/L (>2 mg/dl). In 31 patients suspected of pulmonary emboli but wi thout these confounding factors, the five D-dimer assays were negative in 4 5 to 55% of patients with normal pulmonary angiograms. The negative predict ive value in these patients was 100% by all five latex agglutination assays tested. The latex agglutination assays for D-dimer, when the pulmonary ang iogram is used as the diagnostic endpoint and in the absence of recent surg ery, malignancy, or liver disease, appears to be a clinically useful test i n the diagnosis of acute pulmonary embolism.