This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology and Rheumatology, Subject name: Medicine
[{'content': 'Edrophonium test is diagnostic of \nSelect and explain. \nA. Myasthenia gravis, B. Lambert Eaton syndrome, C. Ammyotropic lateral sclerosis, D. All', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. a (Myasthenia gravis). (Ref. Harrison, Internal Medicine, 16th ed., 2519)Test for diagnosis of MGCommentsAcetyl Choline Esterase/Tensilon/EdrophoniumTest# Most commonly used rapid test.# Highly probable diagnosis if unequivocally positive.# False positive in ammyotropic lateral sclerosis and placebo reactorsAnti-Ach receptor ab assay# 85% positivity in generalized myasthenia gravis.# 50% positivity in ocular myasthenia gravis.# Definitive diagnosis if positive.Repetitive nerve stimulation test# Highly probable.Single fiber EMG# Confirmatory but non-specific', 'role': 'assistant'}]