The latex agglutination test for the diagnosis of meningococcal and haemophilus influenzae meningitis.

103 cerebrospinal fluid (CSF) samples from 55 patients with bacteriologically proven meningitis (caused mainly by Neisseria meningitidis group A and Haemophilus influenzae type b) and from 29 patients with unproved meningitis or other diseases were studied using the latex agglutination (LA) test to demonstrate bacterial antigen in CSF. The tests for N. meningitidis groups A and C and H. ineluenzae type b were found to be rapid, reliable and specific for the serological group of the organism. The demonstration of N. meningitidis group B antigen has not succeeded with the test. Negative results were obtained from culture-positive samples in 4 cases where the bacterial growth was scanty. On the other hand the LA test was clearly positive on 3 occasions in which meningococci did not grow in cultures because of initiated antibacterial therapy or delay before culturing. False-positive results were rare (2 cases). The LA test was found to be at least as sensitive as counterimmunoelectrophoresis in demonstrating bacterial antigens in CSF.