Cerebrospinal fluid, also known as CSF, contains 15-45 milligrams per deciliter of protein, 50-80 milligrams per deciliter of glucose and 0-5 mononuclear cells. CSF contains about two-thirds of the body's serum glucose.
Produced from arterial blood, CSF cushions the brain from trauma and is important to homeostasis of the central nervous system. Cerebrospinal fluid is produced in the lateral and fourth ventricles of the brain by the choroid plexuses. The total volume of CSF in an adult ranges from 140-270 milliliters, and about 600-700 milliliters are produced per day.
Variations in the composition of CSF can indicate pathology. Increased protein content can be indicative of meningitis, subarachnoid hemorrhage or cerebral infarction. In patients with Cretzfeldt-Jacob disease, there are elevated levels of tau protein as well as 14-3-3 proteins that are reliable markers for the condition.
Unusually low glucose levels in CSF is seen in tuberculosis, fungal infections and sarcoidosis. Some conditions, such as Alzheimer's Disease, have specific proteins that can be observed in CSF, such as the tau protein. In multiple sclerosis, the CSF frequently contains fragments of degrading myelin sheathes. In brain cancer, there is an increase in mononuclear cells and malignant cells can be observed on microscopic examination.