What is a cerebrospinal fluid (CSF) analysis?
Cerebrospinal fluid (CSF) is a clear, colorless liquid found in your brain and spinal cord. The brain and spinal cord make up your central nervous system. Your central nervous system controls and coordinates everything you do including, muscle movement, organ function, and even complex thinking and planning. CSF helps protect this system by acting like a cushion against sudden impact or injury to the brain or spinal cord. CSF also removes waste products from the brain and helps your central nervous system work properly.
CSF analysis is a group of tests that look at your cerebrospinal fluid to help diagnose diseases and conditions that affect the brain and spinal cord.
Other names: Spinal Fluid Analysis, CSF Analysis
What is it used for?
CSF analysis may include tests to diagnose:
- Infectious diseases of the brain and spinal cord, including meningitis and encephalitis. CSF tests for infections look at white blood cells, bacteria, and other substances in the cerebrospinal fluid
- Autoimmune disorders, such as Guillain-Barré Syndrome and multiple sclerosis (MS). CSF tests for these disorders look for high levels of certain proteins in the cerebrospinal fluid. These tests are called albumin protein and IgG/albumin.
- Bleeding in the brain
- Brain tumors
Why do I need a CSF analysis?
You may need a CSF analysis if you have symptoms of an infection of the brain or spinal cord, or of an autoimmune disorder, such as multiple sclerosis (MS).
Symptoms of a brain or spinal cord infection include:
- Fever
- Severe headache
- Seizures
- Stiff neck
- Nausea and vomiting
- Sensitivity to light
- Double vision
- Changes in behavior
- Confusion
Symptoms of MS include:
- Blurred or double vision
- Tingling in the arms, legs, or face
- Muscle spasms
- Weak muscles
- Dizziness
- Bladder control problems
Symptoms of Guillain-Barré syndrome include weakness and tingling in the legs, arms, and upper body.
You may also need a CSF analysis if you've had an injury to your brain or spinal cord, or have been diagnosed with cancer that has spread to the brain or spinal cord.
What happens during a CSF analysis?
Your cerebrospinal fluid will be collected through a procedure called a spinal tap, also known as a lumbar puncture. A spinal tap is usually done in a hospital. During the procedure:
- You will lie on your side or sit on an exam table.
- A health care provider will clean your back and inject an anesthetic into your skin, so you won't feel pain during the procedure. Your provider may put a numbing cream on your back before this injection.
- Once the area on your back is completely numb, your provider will insert a thin, hollow needle between two vertebrae in your lower spine. Vertebrae are the small backbones that make up your spine.
- Your provider will withdraw a small amount of cerebrospinal fluid for testing. This will take about five minutes.
- You'll need to stay very still while the fluid is being withdrawn.
- Your provider may ask you to lie on your back for an hour or two after the procedure. This may prevent you from getting a headache afterward.
Will I need to do anything to prepare for the test?
You don't need any special preparations for CSF analysis, but you may be asked to empty your bladder and bowels before the test.
Are there any risks to the test?
There is very little risk to having a spinal tap. You may feel a little pinch or pressure when the needle is inserted. After the test, you may get a headache, called a post-lumbar headache. About one in 10 people will get a post-lumbar headache. This can last for several hours or up to a week or more. If you have a headache that lasts longer than several hours, talk to your health care provider. He or she may be able to provide treatment to relieve the pain.
You may feel some pain or tenderness in your back at the site where the needle was inserted. You may also have some bleeding at the site.
