SALIVA-BASED HIV-ANTIBODY TESTING IN THAILAND

Objective: To determine whether saliva could serve as an alternative t o serum for HIV-antibody testing in an ongoing sentinel surveillance p rogram in Thailand. Methods: Serum and saliva specimens were collected from 1955 individuals in four of the 73 sentinel sites of the nationa l surveillance program in Thailand. Intravenous drug users, female pro stitutes, and men attending sexually transmitted disease clinics were included as participants. All specimens were collected and tested anon ymously. Saliva was gathered with the Omni-Sai collection device and a nalyzed for the presence of HIV antibodies using the immunoglobulin G antibody-capture enzyme-linked immunosorbent assay (GACELISA) laborato ry test, specially designed for low concentration body fluids. Our gol d standard was serum, collected and analyzed independently from the sa liva specimens, using an ELISA test for screening and Western blot for confirmation, Linkage between serum and saliva was blind to the labor atory. A set of HIV-positive and HIV-negative quality assurance sample s for both serum and saliva were also analyzed blind. Results: Finding s are presented as observed in the field, and as quality assurance sam ples after the correction of various field and laboratory errors. The sensitivity of the GACELISA with saliva was 98.0% in the field (298 HI V-positive specimens), 100% after correction of errors (300 HIV-positi ve specimens), and 100% among the quality assurance samples (95 HIV-po sitive specimens). The specificity of the GACELISA was 99.4% in the fi eld (1653 HIV-negative specimens), 99.6% after correction of errors (1 654 HIV-negative specimens), and 100% among the quality assurance samp les (96 HIV-negative specimens). Conclusion: Our findings support othe r published studies that also featured the GACELISA. We conclude that saliva is comparable to serum for assessing HIV antibodies in individu als for surveillance and screening purposes.