There is no test for MS. It would be great if you could give a little blood or pee in a cup and have the result come back from a lab as positive or negative. Unfortunately, it is not that simple.
The standard definition is to have evidence of lesions at two or more locations, at two or more points of time. I have found that the calling of the diagnosis can vary a bit from doctor to doctor. Some are more conservative with making the diagnosis than others. Some are also more experienced with MS and may be more skilled at reading an MRI (especially one done with contrast).
With Dr Fundamental being “very fundamental“, I expected him to be on the conservative end of the spectrum. At the end of my appointment he explained our process to follow while we waited to see what happens. There are numerous diseases that can mimic MS that we needed to rule out. Luckily, many of these have a test for them. With each result that we would get back, either the case for or against it being MS would be strengthened. Eventually we might have a preponderance of evidence supporting a diagnosis one way or the other. That is, if the tests hadn’t identified any other cause.
Next step: Donate a little spinal fluid and more blood.