Unit Code 83370:
Myasthenia Gravis (MG) Evaluation, Adult
Useful For 
Suggests clinical disorders or settings where the test may be helpful
Initial evaluation of patients aged 20 or older with symptoms and
signs of acquired 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 AChR modulating antibody value is (or exceeds) 90% AChR
loss and striational antibody is detected, thymoma is likely. Reflexive
testing will include CRMP-5-lgG Western blot, ganglionic AChR antibody,
GAD65 antibody, and VGKC antibody (which are frequent with thymoma).
Note: Single antibody tests may be requested in follow-up of patients
with positive results documented in this laboratory.
Profile Information A profile is a group of laboratory tests that are ordered and performed together under a single Unit Code. Profile information lists tests performed, inclusive of the test fee, when a profile is ordered and includes reporting names and individual availability.
| Unit Code | Reporting Name | Available Separately | Always Performed |
| 8338 | ACh Receptor (Muscle) Binding Ab | Yes | Yes |
| 83378 | ACh Receptor (Muscle) Modulating Ab | No | Yes |
| 8746 | Striational (Striated Muscle) Ab, S | Yes | Yes |
Reflex Tests Lists test(s) that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial test(s)
| Unit Code | Reporting Name | Available Separately | Always Performed |
| 83107 | CRMP-5-IgG Western Blot, S | No | No |
| 84321 | AChR Ganglionic Neuronal Ab, S | No | No |
| 89165 | Neuronal (V-G) K Channel Ab, S | No | No |
| 81596 | GAD65 Ab Assay, S | Yes | No |
Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.
If AChR modulating antibodies are >= 90% and striational
antibodies are >= 1:60, AChR ganglionic neuronal autoantibody,
glutamic acid decarboxylase autoantibody, neuronal voltage-gated
potassium channel (VGKC) autoantibody, and CRMP-5-IgG Western
blot will be performed at an additional charge.
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Method Name A short description of the method used to perform the test
8338, 83378, 84321, 81596, 89165: Radioimmunoassay (RIA)
8746: Enzyme Immunoassay (EIA)
83107: Western Blot
General Information:
Recommended for initial investigation of: 1) A patient aged 20 or
older with symptoms and signs of acquired MG and 2) A bone
marrow transplant recipient with suspected graft-vs-host disease,
particularly if there is evidence of weakness.
See "Myasthenia Gravis: Adult Diagnostic Algorithm" in
Special Instructions.
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
MG Evaluation, Adult
Ordering Mnemonic An alternate Mayo code (to the Unit Code) for a test
MGEA
Aliases Lists additional common names for a test, as an aid in searching
Acetylcholine Receptor (Muscle AChR) Antibodies
AChR (Acetylcholine Receptor)
Anti-Skeletal Muscle Antibodies
GAD65 (Glutamic Acid Decarboxylase)
Glutamatic Decarboxylase Antibodies (GAD65)
Muscle End-Plate Antibodies
Myasthenia Gravis Antibodies
Myoid Antibody
Neuronal Potassium Channel Ab
Potassium Channel Ab
Soft-MGEA
Striational (Striated Muscle) Antibodies
VGKC
VGPC
Voltage-Gated Potassium Channel Ab
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