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HelpAcetylcholine Receptor (Muscle AChR) Binding Antibody, Serum
Reporting Name
ACh Receptor (Muscle) Binding AbMiscellaneous Test
Useful For
Supporting the diagnosis of autoimmune myasthenia gravis (MG) in adults and children
Distinguishing autoimmune from congenital MG in adults and children or other acquired forms of neuromuscular junction transmission disorders
An adjunct to the test for P/Q-type calcium channel binding antibodies as a diagnostic aid for Lambert-Eaton myasthenic syndrome
Testing Algorithm
This is the primary diagnostic test for myasthenia gravis.
For information see:
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Specimen Type
SerumOrdering Guidance
For the initial diagnostic workup of patients with suspicion of myasthenia gravis, one of the following testing algorithms is recommended:
-Myasthenia Gravis Evaluation with MuSK Reflex Algorithm
-Myasthenia Gravis/Lambert Eaton Syndrome Testing Algorithm
Standalone testing ARBI / Acetylcholine Receptor (Muscle AChR) Binding Antibody, Serum is recommended in certain situations.
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 for 1 week and assayed if sufficiently decayed or canceled if radioactivity remains.
Specimen Required
Patient Preparation: For optimal antibody detection, specimen collection is recommended prior to initiation of immunosuppressant medication.
Supplies: Sarstedt 5 mL Aliquot Tube (T914)
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 1.5 mL
Collect 1.0 mL whole blood in a red or gold top.
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) Performed
Monday through Sunday
TAT: 5 - 8 days
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 US Food and Drug Administration.CPT Code Information
83519
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| ARBI | ACh Receptor (Muscle) Binding Ab | 97558-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 8338 | ACh Receptor (Muscle) Binding Ab | 97558-1 |
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 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: Rose NR, Hamilton RG, eds. Manual of Clinical and Laboratory Immunology. 6th ed. ASM Press; 2002:1005-1012; Waters P, Pettingill P, Lang B: Detection methods for neural autoantibodies. Handb Clin Neurol. 2016;133:147-163. doi: 10.1016/B978-0-444-63432-0.00009-8)
Report Available
3 to 6 daysReject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Special Instructions
Method Name
Radioimmunoassay (RIA)
Forms
If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.