ACETYLCHOLINE RECEPTOR BINDING ANTIBODY

Code
900.0131
Name
ACETYLCHOLINE RECEPTOR BINDING ANTIBODY
Category
None
Department
Send-Out
Start Date
Expiration Date
Synonyms
AChR Binding Ab;Myasthenia Gravis Ab
CPT Codes
83519
Site
SBMF
Reference Test
28053
ATLAS Test Code

ACET REC BIND

Specimen Information

Type

Gold, SST

Volume

1.0 ml

Transport Info

Centrifuge and immediately transfer serum to separate plastic tube within 30 minutes of collection Refrigerated

Fasting Required?
False
Patient Instructions

Reference Range

Negative = Less than or equal to 0.25 nmol/L Equivocal = 0.26-0.49 nmol/L Positive = Equal to or greater than 0.50 nmol/L

Methodology

Radioimmunoassay (RIA)

Clinical Significance

Useful as an aid in the differential diagnosis of Myasthenia Gravis (MG) Myasthenia Gravis (MG) is a neuromuscular disorder characterized by muscle weakness, which in most cases is a result of autoantibody-mediated loss of functional acetylcholine receptors in the neuromuscular junction. More than 85% of MG patients express antibodies to acetylcholine receptors (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 AChR binding to the receptor and lead to poor muscle contraction. • Modulating antibody causes receptor endocytosis resulting in loss of AChR expression. The AChR binding antibody assay is the first choice of assay for confirming a diagnosis of acquired MG. AChR binding antibodies are characteristic of, but not diagnostic of, acquired MG. The test results must be interpreted by a physician in the context of other findings.

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