Cerebrospinal Fluid (CSF) Analysis
A cerebrospinal fluid (CSF) analysis tests a sample of the fluid surrounding your brain and spinal cord to help diagnose infections, autoimmune disorders, and other central nervous system conditions.
Overview
A cerebrospinal fluid (CSF) analysis tests a sample of your CSF for diseases that affect the brain and spinal cord, which make up your central nervous system. Your central nervous system controls and coordinates everything you do, including your ability to move, breathe, see, and think.
CSF is a clear, colorless, watery fluid that flows in and around your brain and spinal cord. It acts as a cushion to protect them from sudden impact or injury, removes waste products from the brain, and helps your central nervous system function properly. Normally, CSF contains substances like water, vitamins, and nutrients, and is free of cells, proteins, and toxins.
What is it used for?
A CSF analysis measures different substances in your fluid to help diagnose:
- Infectious diseases of the brain and spinal cord, such as meningitis (inflammation of the brain and spinal cord) and encephalitis (inflammation of the brain).
- Autoimmune disorders, such as Guillain-Barré Syndrome and multiple sclerosis (MS).
- Bleeding in the brain.
- Brain tumors, including cancers that have spread to the central nervous system.
- Alzheimer's disease.
Why do I need a CSF analysis?
Your health care provider may order this test if you have symptoms of an infection, bleeding, or an autoimmune disorder, or if you have experienced a brain or spinal cord injury. Symptoms of a brain or spinal cord infection include:
- Fever and severe headache
- Seizures
- Stiff neck
- Nausea and vomiting
- Sensitivity to light
- Double vision
- Changes in behavior or confusion
Symptoms of multiple sclerosis (MS) may include:
- Blurred or double vision
- Tingling, numbness, or pain in the arms, legs, body, or face
- Painful muscle spasms
- Weak muscles, particularly in the hands and legs
- Dizziness, balance problems, or clumsy movement
- Bladder control problems
- Fatigue
- Problems thinking or learning new things
Diagnosis & Procedure
To obtain a sample, a provider performs a spinal tap, also known as a lumbar puncture. During the procedure:
- You will lie on your side or sit on an exam table.
- The provider cleans your back and injects an anesthetic to ensure you do not feel pain.
- Once the area is numb, a thin, hollow needle is inserted between two vertebrae in your lower spine.
- A small amount of CSF is withdrawn, which takes about five minutes.
- You must remain very still during the collection.
- You may be asked to lie on your back for an hour or two afterward to help prevent a headache.
Risks and Results
There is very little risk to a spinal tap. You may feel a pinch or pressure during insertion, and some tenderness afterward. Some patients experience bleeding at the site or a headache that may last for several hours or up to a week. If your provider suspects a life-threatening emergency like bacterial meningitis, they may begin treatment before a final diagnosis is confirmed.
In general, results may indicate an infection, autoimmune disorder, or other injury. Your provider will likely order follow-up tests to confirm a diagnosis.