Development of a World Health Organisation International Reference Panel for Anti-HIV

In response to a recommendation made by the "World Health Organisation (WHO) Working Group on Reference Preparations for Testing HBsAg, Anti-HCV and Anti-HIV Diagnostic Kits", a reference panel for anti-HIV consisting of plasma samples representing the major groups and subtypes of HIV has been prepared. The panel consists of solvent-detergent treated anti-HIV-positive human plasma samples that have been diluted 1 in 40 in anti-HIV-negative human serum and freeze-dried and the anti-HIV-positive plasma samples were derived from individuals infected with HIV-1 group M subtypes A, B, C and CRF01_AE, HIV-1 group O and HIV-2. Fifteen laboratories from around the world took part in a collaborative study to evaluate the reference panel for anti-HIV and were requested to test the panel in as wide a range of assays as possible. Where appropriate, serial dilutions were performed and samples tested around their end-points to facilitate the comparison of analytical sensitivity between assays. For qualitative assays such as Western blots and rapid assays, the panel was tested undiluted. Results show that the HIV-negative serum sample was negative in all assays (except for a small number of Western blot assays) and that all HIV-positive samples were detected in all assays, with the exception of an anti-HIV-2 EIA that did not detect most HIV-1 samples and a small number of assays that failed to detect the group O sample. Considerable variability was seen in the end-point titres obtained with the various assays. A report on the study was submitted to the WHO Expert Committee on Biological Standardisation (ECBS) and the panel established as the 1st International Reference Panel for Anti-HIV (code 02/210); a unitage was not assigned to the panel members.