The Diagnostic Utility of D-Dimer Testing in Excluding Pulmonary Embolism in Low-Risk Emergency Department Patients: A Systematic Literature Review

Background: D-dimer testing is commonly used to exclude pulmonary embolism (PE) in emergency department (ED) patients, but its optimal application in low-risk populations is debated. This systematic review evaluates the diagnostic utility of D-dimer testing in excluding PE among low-risk ED patients. Methods: A search of Medline (PubMed), Embase, and the Cochrane Library from inception to October 2024 was conducted for studies assessing D-dimer testing in adult ED patients with suspected PE and low clinical probability. Studies were screened, data extracted, and quality assessed using the Quality assessment of diagnostic accuracy studies- 2 (QUADAS-2) tool. Data on test characteristics, including sensitivity, specificity, and negative predictive value (NPV) were synthesized. Results: Fifteen studies (n=12,534 patients) met inclusion criteria. The pooled sensitivity and specificity of D-dimer testing (500 ng/mL threshold) in low-risk patients were 97.8% (95% CI: 95.9-98.9%) and 54.7% (95% CI: 51.2-58.1%), respectively. The NPV was 99.7% (95% CI: 99.4-99.9%). Using age-adjusted D-dimer thresholds increased specificity to 64.3% (95% CI: 60.1-68.3%) without significantly reducing sensitivity. The YEARS algorithm further improved specificity to 71.8% (95% CI: 67.9-75.4%). Conclusion: D-dimer testing demonstrates high sensitivity and NPV for excluding PE in low-risk ED patients. Age-adjusted thresholds and clinical decision rules like YEARS can enhance specificity without compromising safety, potentially reducing unnecessary imaging. However, clinical judgment remains crucial in interpreting results and managing patients.