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 protein test. They order this test to check your protein levels.
What Is a CSF Protein Test?
A CSF protein test is a medical test that takes a sample of your cerebrospinal fluid. It runs the sample through a series of steps to see how much protein you have in your spinal fluid. This test — also known as immunofixation and protein electrophoresis CSF and CSF protein electrophoresis — uses an electrical current on the fluid sample after it has been removed from your spine.
The current passes through the fluid in the tube and separates the two main types of protein — immunoglobulin and albumin. Healthy fluid has barely any immunoglobulin. Immunoglobulin is often known as IgG.
Usually, your cerebrospinal fluid has 0 milligrams to 4.5 milligrams per deciliter of IgG and 5 milligrams to 34 milligrams per deciliter of albumin.
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.
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 in your spine. This is called a lumbar puncture or spinal tap. 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 about a few hours afterward. This rest period lets the doctor make sure that you can move your legs and that the procedure didn’t cause bleeding that put pressure on your spinal nerves.
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
Rarely, 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.