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

Additional Codes




Reporting Name

ACh Receptor (Muscle) Binding Ab

Useful For

Confirming the diagnosis of myasthenia gravis (MG)


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


Detecting subclinical MG in patients with thymoma or graft-versus-host disease


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

Testing Algorithm

This is the primary diagnostic test for myasthenia gravis.


See Paraneoplastic Evaluation Algorithm in Special Instructions

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type


Specimen Required


Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 2 mL

Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time
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., and 10 p.m.; Saturday 6 a.m.; Sunday 6 a.m. and 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

Method Name

Radioimmunoassay (RIA)