Acetylcholine Receptor (AChR)-binding Antibodies

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Turnaround Time: 2 - 4 days
CPT Code:


Test Type: 1 mL Serum
Stability Time:



Room temperature

14 days


14 days


14 days

Freeze/thaw cycles

Stable x3

Reference Range:

• Negative: 0.00−0.24 nmol/L

• Borderline: 0.25−0.40 nmol/L

• Positive: >0.40 nmol/L


In vitro diagnostic semiquantitative determination of autoantibodies against the acetylcholine receptor in human serum and plasma. This assay is the primary test for confirming the diagnosis of acquired myasthenia gravis.1

Antibodies are not found in congenital myasthenia.

Myasthenia gravis is an acquired disorder of neuromuscular transmission characterized by use-associated muscle weakness and fatigability.1 This condition frequently involves the extraocular muscles and has a strong association with tumor of the thymus (thymoma). The disease has a prevalence of approximately 5 per 100,000 individuals and can occur at any age. In women, the disease usually presents between the ages of 20 and 40 years, while disease onset in men typically occurs later in life.

Autoantibodies to postsynaptic acetylcholine receptors are detectable in the serum of 90% of patients with generalized myasthenia gravis and approximately 70% of patients with ocular myasthenia.1 These autoantibodies interfere with normal neuromuscular function, causing muscle weakness and fatigue. Antibody titers tend to be higher in females and a correlation between antibody titer and degree of muscle weakness has been observed in individual patients. Receptor antibody titers tend to rise several weeks before exacerbations in patients with established myasthenia gravis. Remission after thymectomy is associated with a progressive decline in antibody titers. Consequently, serial measurements of acetylcholine receptor antibodies can be useful in monitoring disease progression as well as the effects of treatment. (Myasthenia gravis is often associated with striational antibody.) AChR-binding antibodies can also be positive in uncomplicated thymoma, Lambert-Eaton myasthenic syndrome, primary lung cancer, and in patients with autoimmune liver disease.1

1. Griesmann GE, Kryzer TJ, Lennon VA. Autoantibody profiles of myasthenia gravis and Lambert-Eaton myasthenic syndrome. In: Rose NR, Hamilton RG, Detrick B, eds. Manual of Clinical Laboratory Immunology. 6th ed. Washington, DC: ASM Press;2002:1005-1012.

Besinger UA, Toyka KV, Hömberg M, Heininger K, Hohlfeld R, Fateh-Moghadam A. Myasthenia gravis: Long-term correlation of binding and bungarotoxin blocking antibodies against acetylcholine receptors with changes in disease severity. Neurology. 1983 Oct; 33(10):1316-1321. PubMed 6684226

Bigazzi PE, Burek CL, Rose NR. Antibodies to tissue-specific endocrine, gastrointestinal, and neurological antigens. In: Rose NR, Friedman H, Fahey JL, eds. Manual of Clinical Laboratory Immunology. 3rd ed. Washington, DC: ASM Press;1986:768-770.

Colvin RB, Bhan AK, McCluskey RT, eds. Diagnostic Immunopathology. New York, NY: Raven Press;1988.

Newsom-Davis J. Diseases of the neuromuscular junction. In: Asbury AK, McKhann GM, McDonald WI, eds. Diseases of the Nervous System. Philadelphia, Pa: WB Saunders Co;1992:197-212.

Protti MP, Manfredi AA, Horton RM, Bellone M, Conti-Tronconi BM. Myasthenia gravis: Recognition of a human autoantigen at the molecular level. Immunol Today. 1993 Jul; 14(7):363-368 (review). PubMed 8363727

Toyka K. Clinical implementation of anti-acetylcholine receptor antibodies. J Neurol Neurosurg Psychiatry. 1994 Mar; 57(3):396-397. PubMed 8158202

Vincent A, Newsom-Davis J. Acetylcholine receptor antibody as a diagnostic test for myasthenia gravis: Results in 153 validated cases and 2967 diagnostic assays. J Neurol Neurosurg Psychiatry. 1985 Dec; 48(12):1246-1252. PubMed 4087000

Collection Details:

Patient Preparation:

No isotopes administered 24 hours prior to venipuncture.

Collection Instructions:

Red-top tube or gel-barrier tube.

If a red-top tube is used, transfer separated serum to a plastic transport tube.