Use of the cytomegalovirus antigenemia (CMV-Ag) assay for the detection of CMV in the blood of AIDS patients

Direct specimen testing was performed on 186 peripheral blood specimens to identify the presence of antigen to cytomegalovirus (viz., the cytomegalovirus antigenemia (CMV-Ag) assay). Confirmatory testing was performed using the shell vial indirect immunofluorescence assay (SVA-IFA), the indirect immunoperoxidase assay (TC-IPA), and conventional tube culture isolation (TC-CPE). The primary reagent for the CMV-Ag assay consisted of anti-CMV monoclonal antibody directed against the internal matrix structural phosphoprotein (1C3; Clonatec-Biosoft, France). The 72-kDa early nuclear antigen (Dupont) was utilized in the SVA-IFA and the TC-IPA. All test systems received an equal number of polymorphonuclear leukocytes in the inoculum. CMV was detected and isolated from 30% (55/186) of the specimens evaluated by either one or a combination of the tests. Detection and (or) isolation of CMV from blood by the CMV-Ag assay, SV-IFA, TC-IPA, and TC-CPE occurred at a rate of 17 (31/186), 12 (22/186), 16 (29/186), and 26% (49/186). Three of 55 positive specimens were identified only by the CMV-Ag assay; each patient in question, however, had at least one previous CMV isolate. No significant differences in sensitivity occurred between the CMV-Ag assay, the SVA-IFA, or the TC-IPA. However, TC-CPE including the blind passage of all negative tube cultures yielded a significantly larger number of positive blood specimens than either of the rapid detection methodologies. The CMV-Ag assay encompasses the benefits of a nonculture system, is simple to perform and easy to read, permits a same-day diagnosis, and requires less reagents than the routinely used SVA-IFA or TC-IPA.(ABSTRACT TRUNCATED AT 250 WORDS)