Ordering Recommendation

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

ACHRBLO

Methodology

Semi-Quantitative Flow Cytometry

Performed

Mon-Sat

Reported

1-4 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 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.5 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 November 18, 2013

Negative: 0-26% blocking
Indeterminate: 27-41% blocking
Positive: 42% or greater blocking

Interpretive Data

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.

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.

Compliance Category

Laboratory Developed Test (LDT)

Note

Hotline History

N/A

CPT Codes

83516

Components

Component Test Code* Component Chart Name LOINC
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.

Aliases

  • AChR Antibody
  • ACHR blocking antibody
  • Muscle nicotinic Acetylcholine Receptor (AChR) Blocking Antibody
  • Myasthenia Gravis Antibodies
Acetylcholine Receptor Blocking Antibody