Meningitis antigen detection: interpretation of agglutination by ultrasound-enhanced latex immunoassay

Detailed instructions for performance and interpretation of ultrasound-enha nced latex agglutination tests for the rapid identification of bacteria cau sing meningitis are described. This recently developed technique, which enh ances the sensitivity of most latex immunoagglutination assays, has been st udied mainly in the context of detection of antigens of meningitis-causing bacteria. The test concentrates on the Wellcogen bacterial antigen kit (Mur ex Diagnostics Ltd) that contains five latex suspensions specific for Haemo philus influenzae type b, Neisseria meningitidis ACYW135, N. meningitidis B / Escherichia coli K1, Streptococcus group B and Streptococcus pneumonine. Light photomicrographs of positive agglutination are shown. Particular atte ntion is paid to the appearance of the latex in negative control samples fo llowing exposure to ultrasound. Guidance is given on interpretation and ass essment in clinical samples.