CSF For Culture & Sensitivity (Radiometric)

Function

Culture and Sensitivity (C&S) of Cerebrospinal Fluid (CSF) is used to identify the specific bacterial or fungal pathogens causing an infection of the central nervous system. The 'Radiometric' method utilizes automated systems that detect CO2 production (via radioactive carbon isotopes) by metabolizing microorganisms, allowing for faster detection than traditional manual plating.

Why it is Ordered

This is a critical, often emergency, test ordered when a physician suspects meningitis or encephalitis. Symptoms prompting this test include:

• Sudden high fever and severe headache.
• Nuchal rigidity (stiff neck).
• Altered mental status or confusion.
• Photophobia (sensitivity to light).

Associated Conditions

Detection of pathogens in the CSF is diagnostic for bacterial meningitis (e.g., S. pneumoniae, N. meningitidis), fungal meningitis (e.g., Cryptococcus), or neonatal sepsis (GBS). The 'Sensitivity' portion of the test determines which antibiotics are most effective against the identified organism. This is life-saving, as bacterial meningitis can be fatal within hours if not treated with the correct antimicrobial agent. A negative culture with high clinical suspicion may prompt testing for viral causes via PCR.