- Lumbar Puncture
Also called a spinal tap, this test requires that a small amount of cerebrospinal fluid (CSF) be taken from your spinal column via a needle that is inserted between your vertebrae. The doctor will send the fluid for evaluation, looking for the presence of oligoclonal bands (an increased number of certain antibodies) -- an indicator of increased immune activity in the spinal fluid.
This test is positive in up to 90% of people with MS, but is not specific to MS; a positive result could indicate another disease or disorder. Depending on results from the MRI, neurologic exam and symptom history, it is possible that you may not have to get a lumbar puncture to receive a definitive diagnosis of MS. (I didn’t.) However, lumbar puncture results can be useful for ruling out other things if there is still a question about diagnosis.
An important note: Lumbar punctures can be done using an x-ray technique known as fluoroscopy, which helps the doctor or technician guide the needle. Lumbar punctures done this way are usually faster and less stressful. However, many people (such as residents, interns and less experienced doctors) are anxious to perform lumbar punctures without fluoroscopy, so that they can get the practice. Do not hesitate to insist on getting a fluoroscopy-guided lumbar puncture, even if you have to get referred to another facility for the test.
- Blood Tests
There is currently no blood test for MS, although scientists are working on this, so there may be one in the near future. Still, a series of tests will be run on your blood to rule out other things, such as Lyme disease, HIV, some rare genetic disorders and a group of diseases known as collagen-vascular diseases (these include lupus, rheumatoid arthritis, scleroderma and others).
Diagnostic CriteriaThere are two basic rules for diagnosing MS:
- The person must have had at least two relapses (an episode where symptoms were present). These episodes must have been separated by at least one month.
- There must be more than one lesion on the brain or spinal cord.
- Negative: Negative means negative. You don’t have MS. It is possible for the doctor to give this diagnosis only when another definite diagnosis is made that can account for your symptoms.
- Possible: This means that you may have symptoms that look like MS, but your tests are normal. No other diagnosis which accounts for the symptoms has been confirmed.
- Probable: Many people fall into this category when they are first seen by a neurologist. You may have symptoms that look like MS and have had two separate episodes separated by at least a month, but normal findings on an MRI. You could also have an MRI that showed only one lesion in your brain or spine. In this case, your doctor will probably recommend repeating the MRI after a certain period of time (for instance, 3 months) to see if any other lesions appear. Depending on how certain your doctor is that you really do have MS, he may recommend that you consider starting an early therapy.
- Definite: Your case fits the diagnostic criteria above. You have had at least two attacks, separated in time, plus at least two areas of demyelination. Believe it or not, many people are relieved to receive a definite diagnosis of MS. I was. I knew what was wrong with me and I knew what I had to do next, rather than continuing to wonder what was causing my problems and worrying that it was something that I was doing.
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