183 Correlation between serum d-dimer testing and computed tomography pulmonary angiography utilisation and diagnostic outcome: a single centre observational study

Introduction Computed Tomography Pulmonary Angiography (CTPA) scans have become readily accessible in healthcare to diagnose Embolism (PE). In real-world settings, there is variability practice patterns with a growing culture of more pragmatic approach related D-dimer testing and subsequent utilisation CTPAs. However, the issue low specificity remains, risking increased unnecessary scanning lower diagnostic yield. We aimed correlate outcome Methods This was single-centre retrospective observational study. collected data on all D-Dimer tests ordered by physicians rule out PE at high-volume acute cardio-respiratory unit. Correlation analysis conducted using Pearson coefficients or Spearman’s correlation, examine correlation CTPA Receiver operator curve (ROC) Area under (AUC) conducted. Results A total 1297 patients had serum levels done PE. The median age 58 years (IQR= 44-72). Only 0.9% (n=11) samples demonstrated D-dimers>20 while rest d-dimers 0.43 (IQR=0.28-0.98) ng/dL. 358 CTPAs were which 55 positive for (15%). Out D-dimers performed, 573 (44.2%) >0.5. Of these patients, 312 underwent (54.5%), 54 (17%) positive. 724 ≤0.5; 46 (6.4%) CTPA, one (2%) thromboembolic disease. There significant full cohort between (r=0.53, CI: 0.49-0.57). no statistically being utilised diagnosis (r=0.03). ROC AUC 0.79 P <0.001. d-dimer cut-off >0.14 yielded 100% sensitivity 72% undergoing our population. Conclusion study suggests over lack impact high likelihood false-positive results clinical context should be taken into consideration prior screening order avoid potential harm resource exhaustion that could result from well as incidental findings relevance controversial. Conflict Interest None disclose