Lumbar Puncture (cont.)

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What is normal CSF?

Normal values for spinal fluid examination are as follows:

  • Protein (15-45 mg/dl)
  • Glucose (50-75 mg/dl)
  • Cell count (0-5 mononuclear cells)
  • Initial pressure (70-180 mm)

These normal values can be altered by injury or disease of the brain, spinal cord or adjacent tissues. The values are routinely evaluated during examination of the spinal fluid obtained from the lumbar puncture. Additionally, spinal fluid is tested for infection in the microbiology laboratory.

What diseases are diagnosed by examination of the CSF?

Spinal fluid obtained from the lumbar puncture can be used to diagnose many important diseases such as bleeding around the brain; increased pressure from hydrocephalus; inflammation of the brain, spinal cord, or adjacent tissues (encephalitis, meningitis); tumors of the brain or spinal cord, etc. Sometimes spinal fluid can indicate diseases of the immune system, such as multiple sclerosis.

What are the risks of an LP?

When spinal fluid is removed during an LP, the risks include headache, brain herniation, bleeding, and infection. Each of these complications are uncommon with the exception of headache, which can appear from hours to up to a day after LP. Headaches occur less frequently when the patient remains lying flat several hours after the procedure.

What are the benefits of an LP?

The benefits of the LP depend upon the exact situation for which it is performed, but an LP can provide lifesaving information.

Medically reviewed by Avrom Simon, MD; Board Certified Preventative Medicine with Subspecialty in Occupational Medicine


"Harrison's Principles of Internal Medicine 18th Edition, e46"
McGraw-Hill, edited by Eugene Braunwald, et. al., 2012.

Medically Reviewed by a Doctor on 6/1/2015