Doctors can diagnose muscle atrophy by observing the muscle mass. And to confirm, the doctor may perform some examinations such as:Blood tests, Muscle or nerve biopsy, Electromyography (EMG), Nerve conduction studies, X-rays, and Computed tomography (CT) scans.(MRI) Magnetic Resonance Imaging: To show internal tissues such as muscle, ligamentsIf muscle atrophy is caused by any other condition, there may need to undergo testing to diagnose the condition.