Sign in →

Test Code ARBI Acetylcholine Receptor (Muscle AChR) Binding Antibody, Serum

Additional Codes


Reporting Name

ACh Receptor (Muscle) Binding Ab

Useful For

A first-order test for the laboratory diagnosis of myasthenia gravis (MG)


Detecting "subclinical MG" in recipients of D-penicillamine, in patients with thymoma without clinical evidence of MG, and in patients with graft-versus-host disease


Distinguishing acquired disease (90% positive) from congenital disease (negative)


Monitoring disease progression in MG or response to immunotherapy


An adjunct to the test for P/Q-type calcium channel binding antibodies as a diagnostic aid for Lambert-Eaton myasthenic syndrome (LES) or primary lung carcinoma

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Specimen Required

Patient Preparation: This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. The specific waiting period before specimen collection will depend on the isotope administered, the dose given and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive specimens received in the laboratory will be held 1 week and assayed if sufficiently decayed, or canceled if radioactivity remains.


Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 1.5 mL

Specimen Minimum Volume

1 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  72 hours

Reference Values

≤0.02 nmol/L

Day(s) and Time(s) Performed

Monday through Friday; 11 a.m., 6 p.m., 10 p.m.

Saturday; 6 a.m.

Sunday; 6 a.m., 10 a.m.

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
ARBI ACh Receptor (Muscle) Binding Ab 11034-6


Result ID Test Result Name Result LOINC Value
8338 ACh Receptor (Muscle) Binding Ab 11034-6

Clinical Reference

1. Lennon VA: Serological diagnosis of myasthenia gravis and distinction from the Lambert-Eaton myasthenic syndrome. Neurology 1997;48(Suppl 5):S23-S27

2. Lachance DH, Lennon VA: Chapter 19, Paraneoplastic neurological autoimmunity. In Neuroimmunology in Clinical Practice. Edited by B Kalman, T Brannagan III. Blackwell Publishing Ltd, 2008, pp 210-217

3. Gilhus NE: Myasthenia Gravis. N Engl J Med. 2016;375(26):2570-2581

4. Nicolle MW: Myasthenia Gravis and Lambert-Eaton Myasthenic Syndrome. Continuum (Minneap Minn). 2016;22(6, Muscle and Neuromuscular Junction Disorders):1978-2005

Method Description

Acetylcholine receptors (a mixture of adult and fetal type) are solubilized from human limb muscle in nonionic detergent and complexed with (125)I-labeled alpha-bungarotoxin to provide antigen. After incubation with patient's serum, an excess of goat-antihuman IgG and IgM is added. Acetylcholine receptor-(125)I-alpha-bungarotoxin complexes to which antibodies have bound will coprecipitate with the total human immunoglobulin. The radioactivity of the washed pellet is determined. All positive results are verified by ruling out false-positive binding of immunoglobulin to (125)I-alpha-bungarotoxin, such as might occur in patients with immune complex disorders or subjects exposed to snake venom products.(Griesmann GE, Kryzer TJ, Lennon VA: Autoantibody profiles of myasthenia gravis and Lambert-Eaton myasthenic syndrome. In Manual of Clinical and Laboratory Immunology. Sixth edition. Edited by NR Rose, RG Hamilton, et al. Washington, DC, ASM Press 2002, pp 1005-1012. Waters P, Pettingill P, Lang B:  Detection methods for neural autoantibodies. Handb Clin Neurol. 2016;133:147-63)

Analytic Time

3 days

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Method Name

Radioimmunoassay (RIA)


If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.