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Myasthenia gravis (MG) evaluation, adult

Lab Section:  Sendout Reference  
Lab Location:  Sendout
Reference Lab: Mayo 
Test ID: LAB3273 
Methodology: Radioimmunoassay (RIA); Enzyme Immunoassay (EIA)
Schedule: Monday-Friday
Reported: 1 week, 3 days
Specimen Requirements:  Collection: 5.0 mL Blood in a Red Top Tube.
Pediatric volume: 3 mL.
Unacceptable conditions: Gross hemolysis; Gross lipemia; Gross icterus
Stability: Ambient 72 hours; Refrigerated 28 days; Frozen 28 days

Notes: 

Reflex Criteria: If acetylcholine receptor (AChR) modulating antibodies are > or =90% and striational antibodies are > or =1:120, then AChR ganglionic neuronal autoantibody, glutamic acid decarboxylase autoantibody, neuronal voltage-gated potassium channel autoantibody, and collapsin response-mediated response-5-IgG Western blot will be performed at an additional charge.

Clinical Indications: Initial evaluation of patients aged 20 or older with symptoms and signs of acquired myasthenia gravis (MG) Bone marrow transplant recipients with suspected graft-versus-host disease, particularly if weakness has appeared Confirming that a recently acquired neurological disorder has an autoimmune basis (eg, MG) Providing a quantitative baseline for future comparisons in monitoring a patient's clinical course and the response to immunomodulatory treatment Raising likelihood of neoplasia If muscle acetylcholine receptor (AChR) modulating antibody value is (or exceeds) 90% AChR loss and striational antibody is detected, thymoma is likely. Reflexive testing will include collapsin response-mediated protein-5-lgG Western blot, ganglionic AChR antibody, glutamic acid decarboxylase (GAD65) antibody, and voltage-gated potassium channel complex (VGKC) antibody (which are frequent with thymoma).

Included in profile: ACh Receptor (Muscle) Binding Ab; ACh Receptor (Muscle) Modulating Ab; Striational (Striated Muscle) Ab, S

Reference Interval:  See patient report or consult reference laboratory website.
CPT Code(s): 83519x4, 83520, 86341, 84182
Last Changed: 11/18/2016 11:50:54
Last Reviewed: 12/27/2016 00:54:23