CSF glucose levels below which value indicate potential pathologies such as septic meningitis?

In the evaluation of cerebrospinal fluid (CSF) for potential pathologies, particularly septic meningitis, glucose levels play a crucial role. Normal CSF glucose levels are typically around two-thirds of serum glucose levels, with reference values generally ranging between 40 to 70 mg/dL. When assessing for conditions such as septic meningitis, a CSF glucose level below 40 mg/dL is particularly significant.

This threshold indicates that there is impaired glucose transport or utilization within the central nervous system, often due to an infectious process that can lead to a consumption of glucose by bacteria or inflammation. Thus, while levels can fluctuate, falling below this critical value is a strong indicator that warrants further clinical investigation and intervention. The emphasis on the 40 mg/dL threshold is based on the association of low glucose levels with bacterial infections, underscoring the importance of this metric in diagnosing meningitis.