Fast Five Quiz: Myasthenia Gravis Workup

Richard Nowak, MD, MS


July 08, 2021

SFEMG provides the most sensitive measure of MG, with a normal SFEMG finding of a clinically weak muscle effectively excluding the diagnosis of MG in most cases.

In demonstrating abnormal neuromuscular transmission, examination of a weak muscle with SFEMG is more sensitive than examination with RNS; however, it is also more technically demanding and requires an experienced clinician.

The anti-AChR antibody test is reliable for diagnosing MG, and at 98%-99% specificity, it is clearly the most specific diagnostic test for MG.

Testing for rheumatoid factor and antinuclear antibodies is an important element of workup to exclude comorbid autoimmunity (ie, systemic lupus erythematosus, rheumatoid arthritis), which may occur with MG.

Learn more about electrodiagnostic studies in patients with suspected MG.


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