Cerebrospinal fluid (CSF) analysis is a laboratory test to measure proteins, sugar (glucose), and other chemicals in the fluid that surrounds and protects the brain and spinal cord.

A sample of CSF is needed. A spinal tap is the most common way to collect this sample. For information on this procedure, see the article on lumbar puncture.

Other methods for collecting CSF are rarely used, but may be recommended in some cases. See also:

• Cisternal puncture
• Ventricular puncture

After the sample is taken, it is sent to the laboratory for evaluation.

See: Lumbar puncture

See: Lumbar puncture

Analysis of CSF can help detect certain conditions or diseases. Specifically, the test looks at the following in a sample of CSF:

• Antibodies and DNA of common viruses
• Bacteria (including that which causes syphilis; see:VDRL test)
• Cell count
• Chloride
• Cryptococcal antigen
• Glucose
• Glutamine
• Lactate dehydrogenase
• Oligoclonal banding to look for specific proteins
• Total protein
• Whether there are cancerous cells present

• Antibodies and DNA of common viruses: None
• Bacteria: No bacteria grows in a lab culture
• Cancerous cells: No cancerous cells present
• Cell count: less than 5 white blood cells and 0 red blood cells
• Chloride: 700 to 750 mg/dL
• Fungus: None
• Glucose: 50 to 80 mg/100 mL
• Glutamine: 6 to 15 mg/dL
• Lactate dehydrogenase: less than 2.0 to 7.2 U/mL
• Oligoclonal bands: 1 or 0 bandings
• Protein: 15 to 45 mg/dL

Note: Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

An abnormal CSF analysis may be due to:

• Cancer
• Hepatic encephalopathy
• Infection
• Inflammation
• Reye syndrome
• Meningitis due to bacteria, fungus, or tuberculosis

For information regarding risks of a spinal tap, see: Lumbar puncture

Griggs RC, Józefowicz RF, Aminoff MJ. Approach to the patient with neurologic disease. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007: chap 418.