Acetylcholine Receptor Blocking Antibody [34459]

Message
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Test Code
ACEBLK


CPT Codes
83519

Preferred Specimen
1 mL serum


Minimum Volume
0.5 mL


Transport Container
Plastic screw-cap vial


Transport Temperature
Room temperature


Specimen Stability
Room temperature: 14 days
Refrigerated: 14 days
Frozen: 30 days


Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Microbially contaminated • Gross hemolysis • Grossly lipemic


Methodology
Radioimmunoassay (RIA)

Setup Schedule
Set up: Sun, Tues, Thurs; Report available: 4-7 days


Limitations
Antibodies may not be found in congenital myasthenia.


Reference Range
<15 % Inhibition


Clinical Significance
Myasthenia Gravis (MG) is an autoimmune neuromuscular disorder characterized by muscle weakness, most commonly due to autoantibody-mediated loss of functional acetylcholine receptors (AChR) in the neuromuscular junction. AChR binding autoantibodies are diagnostic of MG, and are found in 85-90% of MG patients. AChR blocking autoantibodies prevent inter-action of binding antibodies with the AChR. Fewer than 1% of patients have blocking antibodies without binding antibodies. Blocking antibodies are present in about 50% of patients with MG, but rare in other conditions. Therefore, blocking antibodies have utility in ruling out a possible false positive binding assay and detecting the rare patient without AChR binding antibodies.


Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042



Last Updated: November 24, 2021


The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.