Abstract
Immunoassay interference causing unexpected reactive results in magnetic-microparticle-based assays was detected. A systematic evaluation of Liaison Epstein-Barr virus immunoglobulin M showed that 5% of the positive results (0.4% of tested samples) could be explained by such interference. Adding chemical blocking reagents (polyvinylpyrrolidone and polyvinyl alcohol) to the assay buffers partially prevented this phenomenon.