Cerebrospinal Fluid Characteristics

Physical Properties

The cerebrospinal fluid (CSF) is a dynamic and metabolically active fluid that is found in the subarachnoid space between the arachnoid and pia mater, with approximately 140 ml of CSF in the subarachnoid space in adults, a volume that does not vary significantly with height or weight 1
About 800 ml of CSF is produced during 24 hours, meaning that the total volume of CSF is replaced more than 5 times a day 1
The National Comprehensive Cancer Network recommends considering the dynamic and metabolically active nature of CSF in clinical applications 2

The characteristic profile of normal CSF includes normal opening pressure, normal glucose, normal proteins, and absence of pleocytosis, according to the Journal of Infection 3
In pathological conditions such as bacterial meningitis, the CSF typically presents with glucose <35 mg/dL, a CSF/blood glucose ratio of 0.23, a protein level of 220 mg/dL, 2,000 total leukocytes/L, or 1,180 neutrophils/L, as reported in Critical Care Medicine 4
The lactate level in CSF can be useful for distinguishing bacterial meningitis from viral central nervous system infections; in particular, a lactate level in CSF <2 mmol/l generally rules out bacterial disease, according to the Journal of Infection 3