<prompt> A 35 year old female has proximal weakness of muscles, ptosis and easy fatigability. The most sensitive test to suggest the diagnosis is:Muscle BiopsyCPK levelsEdrophonium testSingle fiber EMG  <response>: 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 