Hello. I think you should trust your treating doctor. There are many things that can be detected in csf incuding infections, multiple sclerosis, alzheimer disease etc. So I cannot exactly tell you why he/she is trying to detect till I have had an opportunity to examine you. As for the waiting, I think you should get the test done, because some results take time, and probably your doctor does not want your diagnosis to get delayed. In MS, the treatment has best response when started at the earliest. So I think you should go ahead with your doctor s plans. I have tried to make it as simple as possible. Feel free to contact me for further related information. Best of luck, Dr Mittal