I had a LP. There was no evidence of the banding that is typical of MS in my spinal fluid. So it didn't help me get my MS diagnosis really other than exclude some other diseases.

My LP was the worst experience of my life. I had a vaso vagal (sp?) reaction during my first one. My blood pressure tanked and I became very ill. They had to stop and let me recover. The second one went smoothly until I developed a spinal headache a few days afterwards. That was truly horrible! I became horribly ill everytime I wasn't laying flat on my back. I had to go to the ER and get a blood patch to fix it.

Unless you NEED to do a LP I'd recommend avoiding it.