Quite common to only have MRI findings and negative everything else, MS is diagnosed from clinical presentation and the MRI's .All the other tests whether positive or negative can be caused by other diseases, etc. So they really are used more to rule out other causes, rather than to rule in MS. I have full blown MS (if there is such a thing) and was positive in all the tests, but again the diagnosing criteria is the MRI and clinical presentation of symptoms.
JonM