I have seen it stated that the accuracy of these tests is around 90 - 95% in identifying people with MS when they have actually got MS. I’d be interested to know what research exists to support this figure if anybody knows. Also, if there is any research which has examined the 5-10 % of false negatives with the aim of identifying explanatory factors, or any research correlating this measure of accuracy against the time over which people are thought to have been symptomatic, or against different phases of the relapse/remission cycle.
It’s not so much a matter of accuracy as the fact that some people with MS simply don’t have unmatched oligoclonal bands in their CSF. (There are a number of false positives and negatives too of course - human error affects everything so no test is 100% accurate.)
The LP isn’t actually a test for MS; it’s a test for oligoclonal bands (and other things). There are a number of conditions in which a positive test result can happen; it’s just more common in MS.
Also, once an LP is positive, it’s always positive: it doesn’t vary over time (other than someone who is negative potentially becoming positive).
This might give you a start on any research you want to do:
No idea where these statistics come fom but they confirm what Karen say’s.
A spinal tap (also known as a lumbar puncture) is a procedure whereby a sample of cerebrospinal fluid (CSF) is taken from close to the spinal cord. At the same time a blood sample is taken usually from the arm and a quantity of blood serum is isolated. Both of these samples are then processed using a technique called electrophoresis. A positive spinal tap will produce oligoclonal bands in the CSF but not in the blood serum. These bands indicate a type of immune system activity. Although uncomfortable, the spinal tap itself is often not too painful, whereas in the period following the tap, the patient may experience dizziness, nausea, vomiting and severe headaches, occasionally for as much as a week. There are a few rare but serious side-effects of spinal taps. For more information about spinal taps and how to reduce the possibility of some of the more unpleasant side-effects follow this link: Spinal Tap.
95% of people with a definite diagnosis of MS exhibit oligoclonal bands on a spinal tap. This may sound impressive but so do 90% of people with Sub-Acute Sclerosing Panencephalitis and 100% of people with Herpes Simplex Encephalitis among other conditions. Positive spinal taps are indicative of an immunological response but they are not diagnostic for a particular condition. That 5% of PwMS do not exhibit oligoclonal banding means that spinal taps neither rule-in nor rule-out MS.
The primary purpose of CSF analysis should be to rule out other conditions than multiple sclerosis. Although they can be highly suggestive of MS, they do not, in themselves, provide definitive disgnosis. Indeed, I myself, was given a definite diagnosis based on medical history, clinical examination, MRI and evoked potential tests - I declined to have a spinal tap.
Before MRI, electrophoresis of spinal fluid played a major role in supporting diagnoses and underpinned the Poser criteria. Now, however, these criteria have become overshadowed by MRI and, if an MRI is positive, the new diagnostic criteria (2001) allow for a definitive diagnosis without laboratory support. The old “Laboratory supported Definite MS” has been dispensed with.
However, CSF analysis technology is still advancing and researchers continue to look for definitive molecular markers of MS. Should they find such a marker, spinal taps will reassume their importance. Other researchers are looking into urine and blood for markers and we can hope that they are successful and spinal taps become completely unnecessary to the diagnosis of multiple sclerosis.
is it possiable that a lumbar punture being repeated could then be positive,even though previously it was negative,can we ask for another lumbar punture test to be done.i will never give up,have lived with this so so long now.thankyou.
love boz xxx
Just for interest, here is a link to research that corroborates Karen’s statement that once an LP is positive, it’s always positive
Ive just received my lumbar puncture test results, opening pressure 17,csf protein normal at 0.34,csf glucose 7.2, random glucose 13.9, 2 white cells, 1704 red cells, and no oligoclonal bands. Prior to this had mri full spine showed among other things 1 dymelating plaque. Does this mean ive not got ms?im displaying quite a lot of symptoms.
You’ve put your query in the middle of an old post about LPs so it’s a bit out of context, but here goes my two pennorth anyway.
You previously posted that you had a clear MRI scan (or am I wrong? You said above that you have a plaque in your spine). Add that to a negative LP, and it sounds like you don’t have MS.
But obviously, you need to see your neurologist and ask him/her these questions.