Reliability of D-Dimer test results in deciding the necessity of performing CTA in high risk population to establish the diagnosis of PE

PurposeTo evaluate the reliability of D-Dimer test results in the diagnosis of PE in high risk patients.Patients and methodsThis prospective study was conducted on 98 patients. Mean age was 50 years; age range was 17–88 years. All patients underwent D-Dimer assay. Multidetector CT Angiography (MDCTA) was performed on 128 row multi-slice scanner. Statistical analysis of D-Dimer test values was attempted to assess its diagnostic reliability. Patients were further stratified into two groups: patients with positive D-Dimer test and patients with negative D-Dimer test, and cut-off value patients with negative D-Dimer test and cutoff value was estimated for D-Dimer test results.ResultsStatistical analysis of D-Dimer test values yielded sensitivity 100%, specificity 28% with 100% negative predictive value (NPP) and low positive predictive value (26%). Likelihood ratios were NLR <0.1 and PLR <1. Cutoff value for D-Dimer test results in correlation with CT Angiography results, was 1.45 μg/ml, with diagnostic sensitivity 87% and diagnostic specificity 57%. PLR was 0.43 and NLR was 0.13.ConclusionNegative D-Dimer test is a reliable diagnostic modality to rule out the need for CT Angiography in patients at high risk population of PE. However, positive test results cannot confirm the diagnosis and further testing is warranted.