VALUE OF CEREBROSPINAL-FLUID EXAMINATION IN THE DIAGNOSIS OF MENINGITIS IN THE NEWBORN

Between 1 October 1988 and 30 September 1991 the results of all 896 ce rebrospinal fluid examinations from 736 neonates were correlated with clinical diagnosis, treatment, and outcome. The prevalence of fungal o r bacterial meningitis in babies requiring lumbar puncture was only 0. 95%. Gram staining had a sensitivity of 68% and a positive predictive value of only 46% for the diagnosis of meningitis. Primary cultures di rectly onto agar plates had a sensitivity of 81% and positive predicti ve value of 46%. Broth enrichment cultures did not improve sensitivity and were frequently found to be false positive. Empirical treatment s hould not be altered unless more than a few organisms are seen on Gram staining. Primary cultures are adequate for the diagnosis of fungal a nd bacterial meningitis. Enrichment cultures should be performed only when the Gram stain and/or cell count suggests meningitis is likely. C linicians should be aware that diagnostic tests performed in populatio ns with a low prevalence of disease are likely to generate many false positive results and have a low positive predictive value.