Cerebrospinal Fluid (CSF) Protein by Immunoassay (Tetramethylbenzidine, TMB)

Why This Test Is Done

Your doctor may order this test if you have symptoms like headaches, neck stiffness, confusion, or neurological problems. It’s also used to diagnose or monitor conditions such as meningitis, brain tumors, multiple sclerosis, or traumatic brain injury. Sometimes, it’s part of a broader evaluation for unexplained neurological symptoms or to check for substances like blood or infections in the CSF.

How the Test Works

A small amount of CSF is collected through a procedure called a lumbar puncture (spinal tap). The fluid is then analyzed using an immunoassay method with tetramethylbenzidine (TMB) to detect and quantify proteins. This method is highly sensitive and specific for measuring protein concentration in the CSF.

What to Expect Before the Test

You’ll likely be asked to fast for a few hours before the test if instructed by your doctor. Wear comfortable clothing and bring any necessary medications. On the day of the test, avoid caffeine or alcohol, as they might affect your symptoms or test results. Inform your doctor about any medications you’re taking, especially blood thinners or steroids, as they could influence the procedure or results.

What to Expect During the Test

The lumbar puncture involves inserting a needle into your lower back to collect CSF. You may feel pressure or a slight ache, but it’s usually not painful. You’ll lie on your side with your knees bent, and the procedure takes about 15–30 minutes. You might experience a brief headache afterward, but this usually goes away within a few hours or days.