A 35 year old female has proximal weakness of muscles, ptosis and easy fatigability. The most sensitive test to suggest the diagnosis is:
Single fibre electrophysiology is the most sensitive test for Myasthenia Gravis. The symptoms given in question stem are suggestive of Myasthenia Gravis which is an autoimmune neuromuscular disorder presenting with easy fatigability. Ref: Clinical adult neurology By Jody Corey-Bloomn, Page 332
Muscle Biopsy
CPK levels
Edrophonium test
Single fiber EMG