Age‑adjusted plasma D‑dimer levels in suspected acute pulmonary embolism: a retrospective, single‑center study.

INTRODUCTION The conventional D‑dimer threshold (CDD) is characterized by high sensitivity and low specificity in diagnosing acute pulmonary embolism (PE) in older patients. A higher cut‑off level for D‑dimer has been proposed, aiming at increasing the specificity while maintaining high sensitivity. It is calculated by multiplying the patient's age in years by a coefficient of 10 (YADD10). OBJECTIVES The aim of this study was to validate the clinical value of YADD10 in patients with suspected acute PE and to optimize this threshold to achieve increased specificity paired with high sensitivity. PATIENTS AND METHODS The medical records of 1022 patients with suspected acute PE, hospitalized between the years 2014 and 2016, were retrospectively analyzed. Patients older than 50 years, with complete medical records and good quality of multislice computed tomography (CT) scans were enrolled. The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of the proposed thresholds were calculated and compared with those of the CCD. The number of computed tomography scans that could have been avoided with higher thresholds was determined. RESULTS The final analysis included 321 patients (176 women; mean age, 74.2 years; range, 51-101 years). Acute PE was confirmed in 135 patients. The sensitivity of CDD was 100%, and specificity-5.4%. The use of the YADD10 and YADD11 thresholds (obtained by multiplying by the coefficients of 10 and 11, respectively) resulted in maintaining high sensitivity, with increased specificity of 8.6% (YADD10) and 12.4% (YADD11). The number of unnecessary CT scans was reduced by 7%. CONCLUSIONS The YADD thresholds are characterized by high sensitivity and increased specificity when compared with CDD, thus allowing for a safe reduction of the number of CT scans. A prospective study should be conducted to validate these results.