Test Overview
Test Methodology

RIA (Radioimmunoassay)

Test Usage

Recommended for initial investigation of patients presenting at less than age 20 with a defect of neuromuscular transmission. Seropositivity distinguishes congenital (i.e., genetic) MG from acquired MG. Seronegativity does not exclude the diagnosis of autoimmune MG. A minority of patients lacking detectable AChR antibodies have the recently discovered muscle-specific receptor tyrosine kinase (MuSK) antibodies. MuSK antibody testing is available on request.

Reference Range *

Muscle AChR Binding Ab: <=0.02 nmol/L; Muscle AChR Modulating Ab: 0 - 20%.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Details
Analytic Time

3 - 7 days

Soft Order Code
  • ACh Receptor (Muscle) Binding Antibody
  • AChR Antibodies
  • ACh Receptor (Muscle) Modulating Antibody
  • Acetylcholine Receptor Antibodies
Reference Laboratory
Mayo MGP1
Special Testing
Specimen Requirements
Collection Instructions

Collect specimen in a red top or SST tube. Centrifuge, aliquot serum into a plastic vial and refrigerate.

Yellow Top Tube
Normal Volume
2 mL serum
Minimum Volume
1.5 mL serum
Additional Information

Evaluation includes the following tests: AChR Binding Ab and AChR Modulating Ab. Test sent to Mayo Medical Laboratories.

CPT Code
83519 x2
Fee Code