S1706 Non-Invasive Diagnosis of CMV Colitis in Crohn’s Disease Using Blood CMV DNA: A Meta-Analysis

Introduction: Cytomegalovirus (CMV) colitis is an important differential diagnosis in patients with Crohn’s disease, especially those presenting with severe or steroid-refractory flares. Tissue-based CMV polymerase chain reaction or immunohistochemistry remains the diagnostic gold standard, but endoscopic procedures are invasive, costly, and may be contraindicated in critically ill patients. Plasma or blood CMV DNA testing offers a non-invasive and rapid alternative. However, the diagnostic performance of this modality in Crohn’s disease patients with suspected CMV colitis is not well established. Methods: We conducted a single-arm diagnostic meta-analysis of 4 studies encompassing 641 observations. A random intercept logistic regression model was used to pool sensitivity, specificity, and diagnostic odds ratio (DOR). Heterogeneity was assessed using tau² and I² statistics. The area under the summary receiver operating characteristic (ROC) curve (AUC) was calculated using a bivariate random-effects model to assess overall diagnostic accuracy. Results: The pooled sensitivity of plasma/blood CMV DNA was 66.1% (95% CI: 46.4%–81.4%) and specificity was 86.0% (95% CI: 82.7%–88.8%). The diagnostic odds ratio was 13.68 (95% CI: 4.83–38.69), indicating strong diagnostic discrimination. The AUC was 0.859, reflecting excellent overall accuracy. Heterogeneity was moderate to high for sensitivity (I² = 82.0%) and negligible for specificity (I² = 0%). Positive likelihood ratios ranged from 3.6 to 5.3 across individual studies, while negative likelihood ratios ranged from 0.16 to 0.63. Conclusion: Our findings suggest that plasma or blood CMV DNA testing has high specificity and moderate sensitivity for diagnosing CMV colitis in Crohn’s disease patients. This modality may serve as a valuable non-invasive screening tool, particularly in acutely ill patients where endoscopy is not feasible. However, due to its limited sensitivity, a negative blood CMV DNA test does not exclude CMV colitis, and clinical correlation with tissue-based testing remains essential. Further studies are needed to refine diagnostic thresholds, explore viral load cutoffs, and determine optimal clinical integration.