A cerebrospinal fluid (CSF) chloride test is used to measure the chloride level of a critical component present in CSF fluid. Abnormal levels signal infections (viral, fungal, or pyogenic) or imbalances. Decreased levels are associated with amyotrophic lateral sclerosis, tuberculosis, and fungal meningitis. Monitoring CSF chloride is crucial for neurological diagnosis, providing insights into diverse disorders like meningitis and neurodegenerative diseases.