Mine was negative also, my first neuro screw up the first one, not enough fluid for all the tests. Second done under the scope negative for everything, and a wrong diagnosis from the second because of the negative test, he also refused to order any other tests, couldn`t properly answer questions on his diagnosis, so I asked to see a real doctor.

I got a diagnosis after more testing was done, offered a repeat of the LP but passed on it when the specialist said that even if it was negative again he wouldn`t change his dx.