27th June 2023

A 56-year-old woman presents with fatigue and diplopia. On examination, she has bilateral ptosis

A 56-year-old woman presents with fatigue and diplopia. On examination, she has bilateral ptosis. Pupils are equal and reactive to light. Electromyography demonstrated decrement in evoked action potential following continued stimulation. CT chest is unremarkable.

Select the SINGLE most likely immunological test to aid diagnosis from the list below. Select ONE option only.