a spinal tap would probably show it, if you have it. but my first spinal tap was normal. three days later they did another one and woo hoo, my protein level was really high. sure sign of gbs. also, emg will show the nerve damage. gbs can relapse in the same way as you’re describing. go to a good neurologist and give him ALL of your symptoms and how often you’ve had them. chances are, he/she will persue the above tests mentioned. good luck.