Evaluation of two rapid methods for the detection of herpes simplex virus antigen in patient specimens

An indirect immunofluorescent antibody procedure (IFA) for the detection and typing of herpes simplex virus (HSV) and an enzyme-linked immunosorbent assay (ELISA) procedure were compared with conventional viral culture. Specimens for culture and ELISA were inoculated into serum free viral transport medium (VTM) and, for IFA, onto slides provided in the kit. Tissue cultures (MRC-5 and primary rabbit kidney) were inoculated and examined daily for cytopathogenic effect (CPE). The remaining VTM was frozen at -70 degrees C until tested by the ELISA system. Slides for IFA were stained with HSV common and HSV-2 specific monoclonal antibodies. Of 155 specimens, 47 (30 percent) were unsatisfactory for the IFA test owing to an inadequate number of epithelial cells on the slides. Of 108 adequate specimens, 45 were culture positive; 39 were positive by the IFA test with a sensitivity of 87 percent and a specificity of 90 percent. Of the 39 positives, 29 (75 percent) were correctly classified as type 1 or type 2, six (15 percent) were typed incorrectly, and four (10 percent) were inadequate for typing by the IFA test. All 155 specimens were suitable for testing by the ELISA procedure. Of 55 specimens positive by culture, only 25 (sensitivity 45 percent) were positive by ELISA. However, the specificity was 100 percent. After incubation of two, three, and six days, the tissue cultures detected 71 percent, 89 percent, and 100 percent of the positives, respectively.