Background: Bacterial meningitis is associated with high morbidity and mortality worldwide, with about 1.2 million cases per year resulting in 135,000 deaths.1 The fatality rate can be as high as 70% in patients who are not treated, and one in five survivors may have permanent sequelae in the form of hearing loss, neurologic disability, and/or visual impairment. For these reasons, a rapid diagnostic evaluation with near 100% sensitivity is essential for optimizing outcomes in patients with suspected bacterial meningitis. There are currently gaps in the clinical diagnosis of bacterial meningitis that using PCT serum concentrations may address. One of the limitations to the current gold standard for bacterial meningitis diagnosis (e.g. lumbar puncture) is the likelihood of false negatives when a patient has received antibiotics prior to the lumbar puncture. In instances where a lumbar puncture must be delayed, such as in new onset seizures or history of CNS disease (e.g. CNS mass lesion, stroke, etc.) where a negative CT scan is required prior to lumbar puncture, CSF gram stains and cultures can be less useful in the diagnosis of bacterial meningitis. Another benefit of PCT assays is that results are available much more rapidly than the other diagnostic tests for bacterial meningitis. For example, a CSF culture takes about 72 hours for cultures to return with an identified organism and CRP testing takes about 50 minutes for results to return. In contrast, PCT results are available within 20 minutes from drawing a serum level. Although cost-effectiveness studies have been done showing that a PCT assay is actually a more cost-effective diagnostic tool than both CRP assay and white cell counts, there may still be some hesitation for implementation of the PCT assay in hospitals and labs due to higher costs per test. Also, a serum PCT assay alone cannot provide all the essential information needed in treating bacterial meningitis, such as the identification of the organism present. For this reason, a serum PCT assay cannot replace the standard of care, a CSF analysis, which would mean that the cost of serum PCT assay would be an additional cost on top of the cost of a CSF analysis