Blood Cultures
While direct testing of CSF is the most accurate way to confirm the diagnosis of bacterial meningi- tis, blood cultures can identify the causative organism in the majority of patients. This makes intuitive sense, as most cases of meningitis devel- op hematogenously. The ability of blood cultures to identify the bacteria varies with the organism involved: 80% with Streptococcus pneumoniae, 90% with Neisseria meningitidis and 94% with Hemophilus influenzae.4