On another forum that I go to, there was a post by that forum's host that claimed there is a blood test. (post had just been posted yesterday)

But, she said that the blood test is only used in Europe. Apparently American researchers were not able to duplicate the results of the blood test in their own research, which is why American doctors dont use it as a way to diagnose MS.

So, if you live in the United States, no...there isnt a blood test. If you're in Europe, there might be one. Personally, I would rather have more evidence, like MRI's.