Serum Cytomegalovirus Polymerase Chain Reaction Test Is a Valuable Negative Predictor of Infection in Acute Severe Ulcerative Colitis.

BACKGROUND: Diagnosis of cytomegalovirus (CMV) colitis in the setting of severe ulcerative colitis (UC) remains a clinical challenge. This study aimed to determine the utility of serum CMV polymerase chain reaction (PCR) as a non-invasive test for the diagnosis of CMV superinfection in patients hospitalized with UC. METHODS: This retrospective study included consecutive admitted patients with UC who had serum testing for CMV completed as part of standard hospital procedure and CMV colitis diagnosed by expert pathologists. RESULTS: Two hundred and six patients with UC were included; 13 patients (6%) had histologically confirmed CMV colitis. Eleven of 13 patients with CMV colitis (84%) and 3 of 193 (1.5%) patients without CMV colitis had a positive serum PCR test (p < 0.0001). ROC analysis showed that a CMV PCR level of 259 IU/mL had a sensitivity and specificity of 77% and 99%, respectively, for diagnosis of CMV colitis with an AUC of 0.9 (p < 0.0001). Serum CMV PCR level significantly correlated to the number of inclusion bodies on biopsy specimens with data available (n = 8) (r = 0.8, p = 0.02). CMV positivity did not predict the need for salvage therapy, admission or 1-year colectomy rates. CONCLUSION: Serum CMV PCR has an excellent negative predictive value and demonstrates a strong correlation with CMV positivity on histology. This work supports a rationale for serum CMV PCR testing on admission to assess the risk of CMV colitis in patients with severe UC.