Ordering Recommendation

Assessment of clinical activity of and initial diagnostic testing for myasthenia gravis. For reflexive panel, which contains binding, blocking, and modulating antibodies, refer to Acetylcholine Receptor Antibody Reflexive Panel (2001571).

Mnemonic
ACHRMOD
Methodology

Semi-Quantitative Flow Cytometry

Performed

Sun-Fri

Reported

2-7 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

Serum Separator Tube (SST).

Specimen Preparation

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)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Contaminated, hemolyzed, or severely lipemic specimens.

Remarks
Stability

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

Reference Interval

Effective August 20, 2012

Negative 0-45% modulating
Positive 46% or greater modulating

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.

Compliance Category

Laboratory Developed Test (LDT)

Note
Hotline History
N/A
CPT Codes

83516

Components
Component Test Code* Component Chart Name LOINC
0099521 Acetylcholine Modulating Antibody 30192-9
* 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.
Aliases
  • AChR Antibody
  • ACHR modulating antibody
  • Muscle nicotinic Acetylcholine Receptor (AChR) Modulating Antibody
  • Myasthenia Gravis Antibodies
Acetylcholine Receptor Modulating Antibody