The normal white blood cell count is between 0 and 5. The normal red blood cell count is 0.

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

An increase of white blood cells indicates infection, inflammation, or bleeding into the cerebrospinal fluid. Some causes include:

• Abscess
• Acute infection
• Encephalitis
• Hemorrhage
• Meningitis
• Multiple sclerosis
• Stroke
• Tumor

Finding red blood cells in the CSF may be a sign of bleeding. However, red blood cells in the CSF may also be due to the spinal tap needle hitting a blood vessel while entering the skin or dura.

It is important to see if the red blood cell count returns to normal in samples taken later in the procedure as opposed to earlier. A ratio of the red blood cells to the white blood cells is also calculated to help with diagnosis.

Additional conditions which this test may help diagnose include:

• Arteriovenous malformation (cerebral)
• Cerebral aneurysm
• Delirium
• Dementia
• Epilepsy
• Guillain-Barre syndrome
• Hemorrhagic stroke
• Neurosyphilis
• Primary lymphoma of the brain
• Spinal tumor
• Stroke secondary to syphilis
• Syphilitic aseptic meningitis
• Syphilitic myelopathy