False negative results in anti-HIV ELISA due to insufficient antigen coating of microtitre plates

Since routine ELISA screening of blood donors for anti-HIV antibodies was introduced, much attention has been given to the specificity and the sensitivity of this assay. Most papers deal with false positive reactions while only a few have taken account of false negative results. We have found that insufficient HIV-antigen coating of the microtitre plates can lead to false negative results. It is essential that the producers of the ELISA test kits use control systems which guarantee sufficient antigen coating.