[D-dimer testing in the emergency department: age adjustment, inappropriate use, and ability to predict the extension...

To evaluate whether using D-dimer test results adjusted for age according to the formula proposed by Douma et al. improves diagnostic accuracy; to assess the appropriateness of ordering D-dimer tests on clinical suspicion of pulmonary embolism; and to explore the association of test results with the extension and severity of the embolism.

Retrospective observational study of 1833 cases in which D-dimer testing was ordered for patients in our hospital's emergency department in the course of a year. We calculated sensitivity, specificity, and positive and negative predictive values using our hospital's D-dimer cutoff of 250 μg/mL adjusted for age with a modification of Douma et al.'s formula. When information about pulmonary embolism extension and severity was on record, we assessed the correlation with test results.

Adjusting D-dimer level for age increased the number of true negatives and the specificity and positive predictive value of the test. D-dimer level correlated significantly with the extension of pulmonary embolism (r=0.41, P<.05) but not with clinical severity.

Adjusting the D-dimer test result by age improves accuracy in the diagnosis of pulmonary embolism, even though clinical suspicion in Spain does not follow guideline recommendations. Our findings suggest that Ddimer level correlates with the extension but not the severity of pulmonary embolism.