Ordering Recommendation

Establish or confirm a clinical diagnosis of myasthenia gravis. Includes acetylocholine receptor (AChR) binding and blocking antibodies with reflex to AChR modulating antibodies or MuSK antibodies.


Quantitative Radioimmunoassay (RIA)/Semi-Quantitative Flow Cytometry




3-8 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Serum Separator Tube (SST).

Specimen Preparation

Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 mL)

Storage/Transport Temperature


Unacceptable Conditions

Contaminated, hemolyzed, or severely lipemic specimens.


After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 month (avoid repeated freeze/thaw cycles)

Reference Interval

Test Number
Reference Interval
  Acetylcholine Binding Antibody 0.4 nmol/L or less
  Acetylcholine Blocking Antibody 26 % blocking or less

Interpretive Data

Approximately 85-90 percent of patients with myasthenia gravis (MG) express antibodies to the acetylcholine receptor (AChR), which can be divided into binding, blocking, and modulating antibodies. Binding antibody can activate complement and lead to loss of AChR. Blocking antibody may impair binding of acetylcholine to the receptor, leading to poor muscle contraction. Modulating antibody causes receptor endocytosis resulting in loss of AChR expression, which correlates most closely with clinical severity of disease. Approximately 10-15 percent of individuals with confirmed myasthenia gravis have no measurable binding, blocking, or modulating antibodies.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Components Interpretive Data
Acetylcholine Binding Antibody 0.0-0.4 nmol/L: Negative
0.5 nmol/L or greater: Positive
Acetylcholine Blocking Antibody 0-26% blocking: Negative
27-41% blocking: Indeterminate
42% or greater blocking: Positive

Compliance Category

Laboratory Developed Test (LDT)


If Acetylcholine Receptor Binding Antibody result is greater than 0.4 nmol/L or Acetylcholine Receptor Blocking Antibody result is greater than 26 percent, then Acetylcholine Receptor Modulating Antibody (ARUP test code 0099521) will be added. If Acetylcholine Receptor Binding Antibody result is less than or equal to 0.4 nmol/L, then Muscle-Specific Kinase (MuSK) Ab, IgG (ARUP test code 3006198) will be added. Additional charges apply.

Hotline History


CPT Codes

83519; 83516; if reflexed, add 83516 or 86255; if reflexed add 86256


Component Test Code* Component Chart Name LOINC
0080009 Acetylcholine Binding Antibody 11034-6
0099580 Acetylcholine Blocking Antibody 42937-3
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • AChR Antibody
  • AChR reflex panel
  • Muscle nicotinic Acetylcholine Receptor (AChR) Binding Antibody
  • Muscle-Specific Kinase Antibody by RIA
  • Muscle-Specific Receptor Tyrosine Kinase
  • MuSK
  • MuSK Autoantibody
  • Myasthenia Gravis Antibodies
  • Myasthenia Gravis Antibodies Reflex
Myasthenia Gravis Reflexive Panel