DIAGNOSTIC ACCURACY OF D-DIMER ASSAY IN PULMONARY EMBOLISM USING CTPA AS GOLD STANDARD

Abstract

Objective: To determine the sensitivity and specificity of D-dimer assay for the diagnosis of PE in resource limited settings using CTPA as a gold standard for comparison. Study Design: Cross-sectional study. Place and Duration of Study: Department of Radiology, Combined Military Hospital, Peshawar, from Feb 2019 to Jul 2020. Methodology: A sample of 114 cases of clinically suspected PE presenting in ED were collected by non-probability sampling as per QUADAS 2 domains. D-dimer and CTPA reporting done by separate teams, compilation of data by third team. Using SPSS 23.0, 2×2 contingency table was used to calculate the sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of D-dimer in diagnosing PE. Results: Age range 20-50 years (mean: 40.54 ± 5.02 years). Sixty patients were female (52.3%). D-Dimer levels for the diagnosis of PE: Sensitivity: 92.86%, specificity 89.66%, positive predictive value (PPV): 89.66% and negative predictive value (NPV): 92.86%. Conclusion: The D-Dimer levels are significantly sensitive and specific in the diagnosis of PE: however keeping in view the high mortality of PE, diagnostic accuracy may be further improved by using D-Dimer levels in conjunction with pretest clinical probability rules.