Protein appears in nearly all body tissues, along with your enzymes, blood, and cerebrospinal fluid (CSF). Healthy CSF has a low amount of protein.
If you show symptoms of an infection or nervous system disorder, your doctor might want you to get what's called a CSF (cerebrospinal fluid) protein test. They order this test to check your protein levels. By itself, the test simply measures protein levels; there are other tests your doctor will likely order.
What Is a CSF Protein Test?
A CSF protein test is a medical test that takes a sample of your cerebrospinal fluid. The fluid is examined in a lab for its white blood cell count and the presence of abnormal cells to help determine a cause for either high or low protein levels.
Altogether, healthy spinal fluid has anywhere from 15 milligrams to 45 milligrams per deciliter of protein. If you have more protein in your cerebrospinal fluid — especially IgG — you may have a health condition that needs treatment.
Why Might You Get a CSF Protein Test?
Your doctor may order a CSF protein test if you have some concerning symptoms.
These symptoms could include:
- Fever
- Nausea and vomiting
- Double vision
- Stiff neck
- Severe headache
- Confusion
- Light sensitivity
- Seizures
- Dizziness
- Weak muscles
- Muscle spasms
- Tingling in your face, arms, or legs
Potential health issues that may cause more protein in the spinal fluid include:
- Multiple sclerosis, a disease of the brain and spinal cord where your immune system attacks your body
- Meningitis, when the fluid and membranes around your brain and spinal cord become inflamed
- Brain tumor
- Lyme disease, which is caused by bacteria spread by ticks and can cause fatigue, headache, and fever
- Cancer
- Vasculitis, when your blood vessels become inflamed
- Inflammation of spinal cord
- Other autoimmune diseases that affect your brain or spinal cord
- Bleeding in your brain
What Happens During a CSF Protein Test Procedure?
When you get to your appointment, you will change into a hospital gown. Typically, you will be asked to lie on your side on the exam table with your knees and chin flexed toward your chest. This helps the doctor or nurse practitioner get to your spinal fluid more easily to perform the lumbar puncture (also known as a spinal tap).
The doctor will sterilize the skin around your lower spine. Then they will give you some local anesthetic to numb the area so you don't feel pain.
After the numbing takes effect, the healthcare professional will use a thin, hollow needle and insert it between the bones your spine. The most common place is between the 3rd and 4th vertebrae or the 4th and 5th vertebrae of your spine.
The needle will go in about 3 to 4 inches until it reaches the spinal fluid. The doctor will collect about 1 milliliter to 5 milliliters into a sterile test tube container. The amount collected could be as much as 10 milliliters to 15 milliliters if the doctor’s order asked for other tests, such as cytology (a test to check for cancerous cells) or oligoclonal bands (a test to check for specific protein banding that happens with multiple sclerosis).
Once the care team has finished, they will carefully remove the needle and cover the wound.
You can expect the entire CSF protein procedure to last about 15 minutes, although you will need to lie on your back for an hour or so afterward. This rest period lets the doctor see if you have a spinal headache that can sometimes happen when you sit up or stand after the procedure. These post-lumbar puncture headaches usually go away, but if not, you may need a simple procedure called a blood patch. A long-lasting headache may be a sign that your spinal fluid is leaking. A bit of your blood is injected around the spine to help stop the leakage.
Are There Any Risks to Having a CSF Protein Test?
Serious risks are rare with the procedure, but you may have more minor side effects.
These can include:
- Headaches called “post-lumbar headaches,” which can last for a few hours to a week
- Pain or tenderness where the needle went in
- Slight bleeding at the wound site
Although rare, you may get more serious side effects like infections, inflammation, or severe bleeding. Speak to your doctor or head to an emergency room immediately if you feel unwell.
Next Step: Getting the Results of Your CSF Protein Test
After your CSF protein test, your doctor will contact you with the results.
Standard results. If your results show a number within the standard range, your tests are considered normal.
Nonstandard results. High amounts of protein can show a health condition, as can the color of the fluid. Healthy spinal fluid is clear, so any red, yellow, orange, brown, or cloudy coloration could mean an infection, leaking blood, or another health issue.
Speak to your doctor about whether they want you to get any other tests and how you can work toward better health.
