You are the patient....therefore, you are the boss of your body and of what gets tested and when! However, you are absolutely brilliant to want to not tick off your doc!!

Maybe if you asked if there was anything else that could be ruled in or out before something as invasive (and I'll bet as expensive) as a muscle biopsy. Also, before the any scheduled test, you have the right and should get expense estimates (even if you have good insurance).