Comparison of three assays for cytomegalovirus detection in AIDS patients at risk for retinitis

The purpose of this study was to determine the sensitivity and specificity of three different methods of cytomegalovirus (CMV) detection for AIDS pati ents at risk for CMV retinitis, Patients with CD4(+) counts of <100/mu l an d negative baseline screening eye examinations were tested for CR;IV infect ion by (i) pp65 antigenemia expression in leukocytes, (ii) the Digene Hybri d Capture CMV DNA System, and (iii) the Roche Amplicor Qualitative PCR Test . The incidence of CMV retinitis in our study of 296 patients at the Medica l Center of Louisiana-New Orleans HIV Outpatient Clinic was 7.2 per 100 per son-years (a total of 20 episodes in 18 patients from April 1997 to Februar y 1999), Receiver operating characteristic curves were calculated for each assay to determine optimal cutoff points which maximized the sensitivity an d specificity of each assay. The sensitivities of the assays compared to th e eye examinations were 80% for the pp65 antigenemia assay (cutoff, >0 cell per 1.5 x 10(5) leukocytes), 85% for the Digene assay (cutoff, 1,100 genom e copies/ml of whole blood), and 60% for the Amplicor assay, The specificit ies of the assays were 84, 84, and 87%, respectively. The Digene assay with a cutoff of greater than or equal to 1,400 genome copies/ml gave optimal s ensitivity and specificity and was found to have predictive values equal to those of the more technically cumbersome antigenemia assay.