Initial diagnostic testing for myasthenia gravis. For reflexive panel, which contains binding, blocking, and modulating antibodies, refer to Acetylcholine Receptor Antibody Reflexive Panel (2001571).
Serum Separator Tube (SST).
Separate from cells ASAP or within 2 hours of collection. Transfer 0.5 mL serum to an ARUP Standard Transport Tube. (Min: 0.3 mL)
Plasma. Contaminated, hemolyzed, or severely lipemic specimens.
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
|Positive||0.5 nmol/L or greater|
Approximately 85-90% 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% of individuals with confirmed myasthenia gravis have no measurable binding, blocking, or modulating antibodies.
Laboratory Developed Test (LDT)
|Component Test Code*||Component Chart Name||LOINC|
|0080009||Acetylcholine Binding Antibody||11034-6|
- AChR Antibody
- ACHR blocking antibody
- Muscle nicotinic Acetylcholine Receptor (AChR) Binding Antibody
- Myasthenia Gravis Antibodies