[Utility of D-dimer assay for diagnosing pulmonary embolism: single institute study]

Pulmonary embolism (PE) presents with diverse non-specific signs and symptoms and its diagnosis mainly depends on diagnostic imaging tests which are laborious and not cost-effective, and only a small proportion of patients with suspected PE actually have the disease. The aim of this study was to analyze the utility of D-dimer test for diagnosing PE by categorizing patients into 'PE likely' and 'PE unlikely' groups using Wells score for clinical probability.

One hundred forty consecutive patients with clinically suspected PE, in whom D-dimer and imaging tests were performed were enrolled. Dignosis of PE was made when the imaging tests were positive. Wells scores were retrospectively assigned and the dignostic utility of D-dimer test was analyzed.

Of the 140 patients studied, D-dimer test was positive in 97 and diagnostic imaging tests revealed PE, deep vein thrombosis (DVT), and PE+DVT in 24, 3, and 7 patients, respectively. For the diagnosis of PE, D-dimer test with cutoff value of > or =230 ng/mL showed sensitivity, specificity, and negative predictive value of 96.8%, 39.6%, and 97.7%, respectively. These values were 96.3%, 37.9%, and 91.7% in 'PE likely' group (n=56), and 100%, 38.8%, and 100% in 'PE unlikely' group (n=84). Among 43 patients with D-dimer values of <230 ng/mL, only one patient was diagnosed with PE, who belonged to the 'PE likely' group.

D-dimer test cannot be used as a stand-alone test to diagnose PE, but it can be helpful for exclusion of PE especially in 'PE unlikely' group according to Wells score.