Cerebrospinal fluid ferritin levels in screening for meningism.

To evaluate the potential diagnostic value of the ferritin concentration in cerebrospinal fluid (CSF), measurements were performed with an immunoradiometric assay in 23 control patients and in 65 patients with various neurologic disorders. The geometric mean ferritin level of 3.5 micrograms/L in controls was approximately 10% of the level in normal serum with an upper cutoff level of 10 micrograms/L. Only modest elevations in CSF ferritin concentration were observed in patients with viral meningitis and in those with various non-infectious neurologic disorders. On the other hand, marked elevations ranging between 27 and 322 micrograms/L (geometric mean, 90 micrograms/L) were observed in patients with bacterial or fungal meningitis. Results of the study indicate that CSF ferritin levels are a valuable adjunct in the early evaluation of patients presenting with meningism.