Re-evaluation of D-dimer Thresholds in the Diagnosis of Pulmonary Embolism: Advancing Towards Enhanced Safety and Cost-efficiency

Abstract Introduction: Pulmonary embolism (PE) is a life-threatening condition caused by the obstruction of pulmonary arteries by a thrombus. Diagnosing PE is challenging due to its nonspecific clinical presentation, but early and accurate diagnosis is crucial for timely treatment. The Wells and Geneva scores, along with D-dimer testing, are key diagnostic tools. D-dimer has high sensitivity but low specificity for PE, with a standard cut-off of 0.5 mg/mL. A negative result in low-risk patients can rule out PE, while a positive result necessitates further investigation. Computed Tomography Pulmonary Angiography (CTPA) is the gold standard imaging modality for PE diagnosis. This study investigates whether adjusting the D-dimer cut-off can maintain sensitivity and specificity while potentially improving diagnostic efficiency. Methodology: Data were collected from Monmouth Medical Center, including 878 patients who underwent CTPA in the ED to rule out PE between January 2022 and January 2023. Information on chief complaint, D-dimer levels, CT scan diagnosis, and Geneva score variables were extracted from the EMR. SPSS was used for analysis, with statistical significance set at a p-value < 0.05. Results:The cohort comprised 61.4% (539) females, and the mean age of the sample was 57.2 (±18.3) years. Of the 878 patients, 7.7% (68) were diagnosed with PE via CTPA, while 92.3% were negative. The most common chief complaint was dyspnea (59%), followed by chest pain (33.9%) and cough (17.5%). A significant difference in mean D-dimer levels was observed between patients with positive CTPA (mean = 4.77) and those with negative CTPE (mean = 1.45, p < 0.001). At a D-dimer cut-off of 0.5, sensitivity and specificity were 100% and 12%, respectively. At a cut-off of 0.65, sensitivity remained 100%, while specificity increased to 37%. Discussion: CTPA is an effective method for diagnosing pulmonary embolism (PE); however, it carries certain risks, such as radiation exposure, especially in younger and pregnant patients, as well as the potential for contrast-induced nephropathy (CIN) and allergic reactions. In contrast, D-dimer testing presents a cost-effective and non-invasive alternative for assessing PE. Our study demonstrated that raising the D-dimer cut-off from 0.5 to 0.65 would maintain the sensitivity at 100%, enhance the specificity, and would significantly reduce the number of patients requiring CTPA. This strategy may reduce radiation exposure and healthcare costs while preserving diagnostic accuracy.