The anti-acetylcholine receptor antibody test is specific for myasthenia gravis. Anti-ACh receptor (AChR) antibodies are measured by an immunoprecipitation assay in which AChR is labelled with iodine alpha-bungarotoxin, a snake venom which binds specifically to AChR, and incubated with serum
On an individual level, there is a good correlation between the antibody titre and the severity of the disease but the relationship does not apply generally, presumably because of antibody heterogeneity.
Patients negative for this test but suspected of myasthenia on clinical grounds should be tested for antibodies to other determinants of neuromuscular junction function.
Last reviewed 01/2018