A stool test in patients with active ulcerative colitis helps exclude cytomegalovirus disease.

Objectives: In severe ulcerative colitis (UC) bowel biopsy is recommended to detect the cytomegalovirus (CMV) infection capable of complicating the course of the disease. Histopathology with immunohistochemistry (IHC) is time-consuming, and a blood polymerase chain reaction (PCR) for CMV DNA is used as an alternative, notwithstanding nothing more than a moderate correlation between the two. We aimed to detect CMV DNA in the stools of patients with active UC, and to compare the results with CMV IHC in bowel biopsies. Materials and methods: Measurement of CMV DNA in stools (copies/ml) entailed PCR, while biopsies assessed inflammation activity (Geboes scale), as well as counts of numbers of CMV IHC-positive cells/biopsy. The severity of UC was assessed using the Mayo score, stool calprotectin and concentrations of C-reactive protein in the blood. Results: 89 of the above pairs of tests for CMV were performed among 75 patients. CMV was detected in 36/89 stool specimens and 19/89 bowel biopsies. The sensitivity of the stool-CMV PCR was thus 84.7%, while specificity was of 71.4%. The negative predictive value was 94.3% and the positive predictive value 44.4%. No difference in the severity of UC was noted between the stool CMV DNA positive and negative groups. Similarly, there was no difference in the severity of UC between the CMV IHC positive and negative groups, except for the Geboes score, more often found to be higher in CMV IHC-positive patients ( p  = .002). Conclusions: CMV DNA was detected in the stools of 40.4% of patients with active UC. A negative test result may help to exclude bowel CMV disease.