Order Mnemonic:

ACHRMOD

Dept Name:

SEND OUTS

Reference Lab:

ARUP

Ref. Lab Test No.:

0099521

Refer to:

ARUP Labs

Transport:

Serum, refrigerated

Processing:

Centrifuge and pour off into transport tube.

Stability After
Processing:

Ambient: 2 hours
Refrigerated: 1 week
Frozen: 1 month (avoid multiple freeze/thaw cycles)

Minimum Testing
Volume:

0.3 mL

Unacceptable Conditions:

Severely lipemic, contaminated, or hemolyzed specimens.

Reference Range:

Negative: 0-20% modulation
Indeterminate: 21-25% modulation
Positive: 26% or greater modulation

Additional Info:

Approximately 90% of patients with myasthenia gravis (MG) express antibodies to the acetylcholine receptor (AChR), which can be divided into binding, blocking, and modulating antibody. Binding antibody can activate complement and lead to loss of AChR. Blocking antibody may impair AChR binding 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% of individuals with confirmed myasthenia gravis have no measurable binding, blocking, or modulating antibody.

Methodology:

Radioreceptor Assay

CPT Codes:

83519

Performed:

Sun, Mon, Wed, Thu

Reported:

2-4 days

NCD/LCD ABN Required:

No