Chromogenic Limulus amebocyte lysate assay as an aid in the diagnosis of meningitis.

Cerebrospinal fluids (CSFs) from 146 patients with suspected meningitis were screened by a recently introduced, rapid and sensitive chromogenic Limulus amebocyte lysate (CLAL) assay for endotoxin. Fifty-eight of these CSFs were screened as well for bacterial antigens by CIE, latex and/or coagglutination techniques. A total of 68 CSFs were positive by either culture and/or at least one of the antigen screens. The overall sensitivity of the CLAL assay was 93% with a specificity of 100%. However, the assay's sensitivity for community - acquired meningitis due to Haemophilus influenzae type b and Neisseria meningitidis was 100%. In this group the assay's sensitivity was better than those of direct gram stain (62%), culture (80%), and commercially available, rapid antigen detection methods (89%). Used judiciously, the CLAL assay is a cost-effective, helpful adjunct test for the diagnosis of gram-negative meningitis.