Cerebrospinal fluid (CSF) analysis is a group of laboratory tests that measure chemicals in the fluid that surrounds and protects the brain and spinal cord. The tests may look for proteins, sugar (glucose), and other substances.
How the Test is Performed
A sample of CSF is needed. A lumbar puncture, also called a spinal tap, is the most common way to collect this sample. Less common ways to take a fluid sample include:
- Cisternal puncture
- Removal of CSF from a tube that is already in the CSF, such as a shunt, ventricular drain, or pain pump
- Ventricular puncture
After the sample is taken, it is sent to the laboratory for evaluation.
How to Prepare for the Test
Your health care provider will tell you how to prepare for lumbar puncture.
Why the Test is Performed
Analysis of CSF can help detect certain conditions and diseases. All of the following can be, but are not always, measured in a sample of CSF:
Normal results include:
- 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 (all mononuclear) and 0 red blood cells
- Chloride: 110 to 125 mEq/L (110 to 125 mmol/L)
- Fungus: None
- Glucose: 50 to 80 mg/dL or 2.77 to 4.44 mmol/L (or greater than two-thirds of blood sugar level)
- Glutamine: 6 to 15 mg/dL (410.5 to 1,026 micromol/L)
- Lactate dehydrogenase: less than 2.0 to 7.2 U/mL (0.3 to 0.12 microkat/L)
- Oligoclonal bands: 0 or 1 bands that are not present in a matched serum sample
- Protein: 15 to 60 mg/dL (0.15 to 0.6 g/L)
Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.
The examples above show the common measurements for results for these tests. Some laboratories use different measurements or may test different specimens.
Note: mg/dL = milligrams per deciliter and mmol/L = millimoles per liter
What Abnormal Results Mean
An abnormal CSF analysis result may be due to many different causes, including:
Cerebrospinal fluid analysis
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Review Date 6/1/2015
Updated by: Daniel Kantor, MD, Kantor Neurology, and Immediate Past President of the Florida Society of Neurology (FSN), Coconut Creek, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.