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Test Code ACBLAB Acetylcholine Receptor  (AChR) Blocking Antibody, Serum

Performing Laboratory

LabCorp Burlington, NC


This assay measures antibodies that inhibit the binding of radiolabeled alpha-bungarotoxin (α-BTX) to solublized muscle AChR.


TAT: 4 - 7 Days

Specimen Requirements

Container/Tube:  Gold-top tube(s)

                               No isotopes administered 24 hours prior to venipuncture

Specimen:  1 mL of serum (0.3 mL min)

Transport Temperature:  Refrigerate

Stability:  13 Days Room Temperature, Refrigerated and Frozen

Rejection: Gross hemolysis; gross icterus; gross lipemia

Reference Values

Negative:      0 - 25

 Borderline:  26 - 30

 Positive:         >30



A Results of this test are labeled for research purposes only by the assay's

manufacturer. The performance characteristics of this assay have not been

established by the manufacturer. The result should not be used for treatment

or for diagnostic purposes without confirmation of the diagnosis by another

medically established diagnostic product or procedure. The performance

characteristics were determined by LabCorp.

Test Classification and CPT Coding



LONIC;    11561-8

Computer Interface Code

PDM # 5901710

Useful For

This assay is a secondary test for confirming the diagnosis of acquired myasthenia gravis

Myasthenia gravis is an acquired disorder of neuromuscular transmission characterized by use-associated muscle weakness and fatigability.1 This condition frequently involves the extraocular muscles and has a strong association with tumor of the thymus (thymoma). The disease has a prevalence of approximately 5 per 100,000 individuals and can occur at any age. In women, the disease usually presents between the ages of 20 and 40 years, while disease onset in men typically occurs later in life. AChR blocking antibodies are observed in 52% of patients with autoimmune myasthenia gravis.1 These autoantibodies interfere with normal neuromuscular function, causing muscle weakness and fatigue. Approximately 1% of individuals are positive for AChR blocking antibodies in the absence of AChR binding antibodies.1


1. Griesmann GE, Kryzer TJ, Lennon VA. Autoantibody profiles of myasthenia gravis and Lambert-Eaton myasthenic syndrome. In: Rose NR, Hamilton RG, Detrick B, eds. Manual of Clinical Laboratory Immunology. 6th ed. Washington, DC: ASM Press;2002:1005-1012.