Limulus lysate test for gram-negative bacterial meningitis. Bedside application.

The limulus lysate on cerebrospinal fluid was evaluated in 335 infants and children as a method for the rapid diagnosis of Gram-negative bacterial meningitis. Positive limulus tests were obtained within one hour in 33 of 34 cases of Hemophilus influenzae meningitis; four additional patients with Gram-negative meningitis also showed positive limulus lysate tests. Conversely, 13 patients with Gram-positive bacterial meningitis all yielded negative limulus assays. All 48 cases of aseptic meningitis and 236 children with no meningitis showed negative limulus assays. Antibiotic therapy prior to hospitalization did not vitiate the validity of the test. A bedside adaptation of the limulus test, performed by house officers and medical students, showed approximately 98% agreement with the laboratory assay.