Elimination of False-Positive Results in a Luminex Assay for

In our 14-valent Luminex assay for pneumococcal antibodies, we identified two groups of sera that caused false-positive results. The first group bound nonspecifically to the Luminex microspheres. The second group reacted specifically with bovine serum albumin (BSA). We describe here methods that eliminated the false-positive reactivity of both groups. We previously described a multiplexed pneumococcal anti-body assay based on the Luminex xMAP technology (11). Sev-eral other laboratories subsequently also described multi-plexed Luminex assays for detecting these antibodies (1, 6, 15). In addition, the Luminex xMAP technology has been used for multiplexed assays to measure antibody responses to vaccines for other infectious diseases, including those caused by Neis-seria meningitidis, Haemophilus influenza type b, Bordetella per-tussis, Clostridium tetani, Corynebacterium diphtheriae, Bacillus anthracis, and papilloma virus (3, 4, 10, 12, 13, 17). Waterboer et al. (18) documented an intrinsic problem with the use of th