Utility of D-dimer assay for diagnosing pulmonary embolism: Single institute study

Abstract

Background : 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 costeffective, 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. Methods : 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. Results : 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 ≥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. Conclusions : 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.