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Background: Detection of HIV-1 antibodies in individuals at risk for infection remains an important element in understanding evolving epidemiological trends. This study evaluated the utility of a new, highly sensitive ELISA for HIV-1 antibody detection in several at-risk populations.

Methods: Sensitivity of the Vironostika HIV-1 Plus O Microelisa System (HIVOTEK) was enhanced over the current FDA licensed assay with inclusion of purified viral envelope proteins and a synthetic peptide from an HIV-1 Group O isolate. Assay analytical sensitivity was determined by testing 12 commercially available HIV-1 seroconversion panels and 10 terminal dilution panels. Serum specimens from at-risk individuals from four populations (prison inmates, an HIV outreach clinic, STD clinic, and inner city emergency room) were tested with HIVOTEK and an FDA-licensed assay.

Results: With all seroconversion panels tested, the HIVOTEK assay reported a reactive result on the average 8 days prior to the FDA licensed assay based on specimen collection interval. In terminal dilution studies, the HIVOTEK assay was found to be 26 times more sensitive than the current assay. Of 1500 high-risk individuals tested, 110 specimens were reactive with both assays and were confirmed positive by Western blot. The HIVOTEK assay detected an additional 6 specimens, all indeterminate by Western blot (3 with specific glycoprotein bands) and one with an IFA-positive result.

Conclusions: The improved analytical sensitivity of the HIVOTEK assay should enable earlier detection of HIV-1 antibodies in populations at-risk for acquisition of HIV infection.

Keywords: HIV-1; Antibody detection; High risk populations