We are using infectious disease test kits consisting of positive serum diluted with negative pooled serum(P-S) and positive control(P-C). In two anti-HIV antibody tests the results for both P-S and P-C fluctuated between positive and negative depending on the lot No. of the reagent. In Western blot tests carried out to confirm the tests, the P-C was found to be positive and the P-S tests were both inconclusive. We speculated that the P-S had very weak antibodies that reacted differently from patient samples.
Manufacturers of such kits, however, must supply reagents with appropriate reactivity, so it is important that they be informed of inconsistencies that could invalidate cut-off values and lead to false-positives and false-negatives.


*1Department of Clinical Laboratory, Kanagawa Prefectural Atsugi Hospital, Atsugi 243-0004

【Key Words】infectious disease tests, control serum, anti-HIV antibody assay