False-positive latex agglutination test for Neisseria meningitidis groups A and Y caused by povidone-iodine antiseptic contamination of cerebrospinal fluid.

The cerebrospinal fluid of a patient yielded a positive latex agglutination test for Neisseria meningitidis groups A and Y. The latex agglutination results were not consistent with clinical and other laboratory findings. An investigation determined that the positive agglutination test was caused by contamination of the cerebrospinal fluid with povidone-iodine during the lumbar puncture.