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Test Code ACBLAB Acetylcholine Blocking Antibody, Serum

Performing Laboratory

Quest Diagnostics Nichols Inst San Juan Capistrano


Radioimmunoassay (RIA)

Reference Values

<15 % Inhibition

Test Classification and CPT Coding



LONIC;    11561-8

Physician Office Specimen Requirements

Container/Tube:  Gold-top tube(s)

Specimen:  1 mL of serum (0.5 mL min)

Transport Temperature:  Refrigerate


Stability:  14 days Refrigerated

Day(s) and Time(s) Performed

Sunday, Tuesday and  Thursday


TAT- 4 - 7 Days

Computer Interface Code

PDM # 5901710

Useful For

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.