ACETYLCHOLINE RECEPTOR ANTIBODIES - plasma or serum

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Specimen: 5 mL blood in plain tube on melting ice, or blood spots on kit filter paper.

Method: Competitive binding assay using radio-labelled a-bungarotoxin acetylcholine receptor. Radio-immunoassay using cell lines.

Reference Interval: Qualitative test. Positive result is significant.

Application: Diagnosis of myasthenia gravis; monitoring disease activity.

Interpretation: More than 90% of patients with generalised myasthenia gravis, and about 60% of ocular myasthenics have detectable acetylcholine receptor antibodies. The test is positive in less than 1% of non-myasthenics and a positive result usually indicates a related disorder.

Reference: Vincent A et al. J Neurol Neurosurg Psychiatry 1985; 48: 1246.

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