 - Positive serum anti-acetylcholine receptor binding antibodies muscle acetylcholine receptors, AchRAb 1.00 nmolL. AchRAb levels of 0.50-0.99 nmolL will be acceptable if there is another confirmatory test for MG, including single-fiber electromyography EMG, repetitive nerve stimulation, or unequivocal edrophonium testing. 