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pubmed:otherAbstract |
PIP: 21 laboratories participated in an international collaborative study to evaluate potential international reference reagents for measurement of antibodies to human immunodeficiency virus (HIV). Given inherent differences between the principles of currently used assays (based on enzyme-linked or radioimmunosorbance, immunofluorescence, immunoblotting, or immunoprecipitation) and batch-to-batch variations in the preparations of reagents and kits, there is an urgent need for well-characterized reference materials that can be used to define the reliability and sensitivity of the tests, for quality control of batches, and as common references between laboratories. The 7 human sera tested included 1 reactive against HIV and 1 unreactive. The study was designed to identify the coded preparations that reacted with HIV antibodies and to ascertain the minimum amount of the reactive samples that could be detected in the methods routinely used by the participants. Participants carried out single or duplicate assays for individual manufacturer's ELISAs or by their local methods. The proposed positive international reference reagent (coded A) reacted strongly in all immunoassays and gave all the expected bands in immunoblot systems using HIV-related virus strains as antigens. The unreactive serum (coded E) was negative by ELISA and immunoblots. Although the end-points determined by ELISAs varied considerably between laboratories, even when the same commercial kit was used, this variation was reduced somewhat when the reactivities of the samples were expressed relative to preparation A. It is concluded that the proposed international reference reagent A may have value as a qualitative check on the specificity of assays, in calibrating positive controls included in kits and other assays in arbitrary units, in calibrating detection limits in arbitrary units, and for calibrating immunoblots, especially for defining the optimal amounts of antigen and determining the relative mobilities of the major HIV peptides and glycopeptides.
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