A lumbar puncture (spinal tap) is a common test doctors use to check for signs of MS in your spinal fluid. But a lumbar puncture on its own isn’t enough to confirm an MS diagnosis.
Diagnosing multiple sclerosis (MS) involves several steps. One of the first steps is a general medical evaluation that may include:
- a physical exam
- a discussion of any symptoms
- your medical history
If your doctor suspects that you have MS, you may need to take more tests. This includes a lumbar puncture test, also known as a spinal tap.
This article explains how a spinal tap is used to diagnose MS and what the procedure is like.
A lumbar puncture involves testing your spinal fluid for signs of MS. To do so, your doctor will insert a needle into the lower part of your back to remove spinal fluid.
A lumbar puncture is the only way to directly and accurately determine the amount of inflammation in your central nervous system.
It also shows the activity of your immune system in these parts of your body, which is important for diagnosing MS.
Typically, no special preparation is needed for a spinal tap procedure. However, it’s always best to ask your doctor if you need to stop certain medications (such as blood-thinning medications) prior to the procedure.
During a lumbar puncture, spinal fluid generally is drawn from between your third and fourth lumbar in your lower spine using a spinal needle. Your doctor will ensure that the needle is positioned between your spinal cord and the cord’s covering or the meninges when drawing fluid.
The whole procedure typically takes about
Following the procedure, you may be asked to remain lying down for a few hours or drink fluids such as caffeine to
Most spinal fluid results are available 2 to 3 days after the procedure. More specialized tests may take up to one week to obtain the results.
A spinal tap can tell you whether the amount of protein, white blood cells, or myelin in your spinal fluid is too high. It can also reveal whether the fluid in your spine contains an abnormal level of immunoglobulins.
Analyzing your spinal fluid can also show your doctor whether you might have another condition and not MS. Some viruses can cause signs and symptoms similar to MS.
A lumbar puncture should be given along with other tests to confirm a diagnosis of MS. The procedure can reveal issues with your immune system.
However, other conditions that affect your nervous system, like lymphoma and Lyme disease, can also show high levels of immunoglobulins and proteins in your spinal fluid, hence the need to confirm a diagnosis with additional tests.
A spinal tap can reveal an abnormal immune response caused by MS. However, other conditions can also cause a similar immune response in the spinal fluid. In addition, roughly 5% to 10% of people with confirmed MS don’t show any abnormalities in their spinal tap results.
For these reasons, multiple other testing methods are needed to diagnose MS.
MS is difficult for doctors to diagnose because no single test can confirm or deny a diagnosis.
Because MS shares symptoms with other health problems, your doctor needs to determine whether it’s MS that’s causing your symptoms and not another condition.
In addition to a spinal tap, other tests your doctor might perform to rule out or confirm a diagnosis of MS include:
- blood tests (can help rule out other conditions)
- magnetic resonance imaging (MRI) (to detect lesions on your brain)
- evoked potential test (to detect nerve damage)
A lumbar puncture is a common test used to diagnose MS, and it’s a relatively simple test to perform. It’s generally the first step in determining whether you have MS if you’re showing symptoms.
Your doctor will determine what tests are needed to confirm a diagnosis of MS.