Sensitivity of HIV antibody detection in saliva

To assess the sensitivity and specificity of HIV antibody detection in saliva we tested matched serum and saliva samples from HIV-infected and uninfected individuals. Saliva specimens were collected by two different devices of the Salivette system and stored at different temperatures. Samples were tested for HIV antibodies by two commercially available enzyme-linked immunosorbent assays (ELISAs; Wellcome, Biotest). HIV antibodies were detected in 98.5% (Wellcome) and 97.8% (Biotest) of the saliva samples (standard Salivettes) from 135 seropositive individuals. Using the Salivettes flavoured with citric acid the sensitivity was only 22.9%. No reactions in ELISA were found in saliva from HIV-seronegative individuals. Salivary HIV-specific IgA was detected in 90% of seropositive individuals. All positive saliva samples stored at room temperature were still reactive after 20 days; of those stored at 37 degrees C, 23 out of 24 were positive when retested on day 5. Sensitivity of HIV antibody detection in saliva samples dried onto filter paper was 100% when a minimum of 100 microliters of saliva was used. HIV antibody testing in saliva is an efficient tool for large scale epidemiological studies when standard Salivettes are used for sample collection. Saliva samples can be stored in Salivettes or dried onto filter paper for several days at room temperature and under tropical conditions (37 degrees C).