Magnitude of d-dimer matters for diagnosing pulmonary embolus.
Am J Emerg Med. 2013 May 16;
Authors: Shah K, Quaas J, Rolston D, Bansal S, Bania T, Newman D, Wiener D, Lee J
OBJECTIVE: The objective of this study is to determine whether the magnitude of the d-dimer correlates with a higher likelihood of pulmonary embolus (PE). METHODS: We performed an electronic chart review at our academic, tertiary care center, annual emergency department (ED) census greater than 100000. All patients with a chest computed tomographic (CT) scan with intravenous contrast and an elevated d-dimer level obtained in the ED between January 2001 and July 2008 were identified. Specific, predetermined, predefined data elements including sex, age, d-dimer level, and final ED diagnosis were recorded by a hypothesis-blinded extractor using a preformatted data form. d-dimer level less than 0.58 μg/mL constitutes the normal laboratory reference range for our turbidometric d-dimer assay. Data were analyzed using standard statistical methods, and a linear regression analysis was performed for correlation analysis of d-dimer and diagnosis of PE. RESULTS: We identified 544 subjects who had both a chest CT scan performed and an elevated d-dimer level obtained in the ED. Fifty-eight subjects (10.7%; mean d-dimer, 4.9 μg/mL) were diagnosed with PE, and 486 (89.3%; mean d-dimer, 2.0) did not have a PE. The percentages of PE diagnoses for d-dimers in the ranges 0.58 to 1.0, 1.0 to 2.0, 2.0 to 5.0, 5.0 to 20.0, and greater than 20.0 (n = 11) were 3.6%, 8.0%, 16.2%, 35.3%, and 45.5%, respectively. The positive predictive value of PE for d-dimer level cutoffs of greater than 0.58, greater than 1.0, greater than 2.0, greater than 5.0, and greater than 20.0 was 10.7%, 14.6%, 22.2%, 37.8%, and 45.5%, respectively. Increasing d-dimer values were strongly correlated with the presence of PE (odds ratio, 1.1685 per stratum; P < .001). CONCLUSION: Increasing magnitude of d-dimer correlates with increasing likelihood of PE diagnosed by CT angiography.
PMID: 23685058 [PubMed - as supplied by publisher]