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Unit Code 83369:
Myasthenia Gravis (MG)/Lambert-Eaton Syndrome (LES) Evaluation

Useful For Suggests clinical disorders or settings where the test may be helpful

Confirming the autoimmune basis of a defect in neuromuscular

transmission (eg, MG, LES)

 

Distinguishing LES from 2 recognized autoimmune forms of MG

 

Raising the index of suspicion for cancer, particularly primary

lung carcinoma (N-type calcium channel antibody)

 

Providing a quantitative autoantibody baseline for future comparisons

in monitoring a patient's clinical course and response to

immunomodulatory treatment.

 

Note:  Single antibody tests may be requested in the follow-up of

              patients with positive results previously 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 
 81185   P/Q-Type Calcium Channel Ab No Yes
 81184   N-Type Calcium Channel Ab No Yes
 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

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 antibody 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

• Myasthenia Gravis/Lambert Eaton Syndrome Diagnostic Algorithm 

Method Name A short description of the method used to perform the test

81184, 81185, 8338, 83378, 84321: Radioimmunoassay (RIA)

8746: Enzyme Immunoassay (EIA)

83107: Western Blot

General Information:

This evaluation is recommended for patients presenting with an

acquired defect of neuromuscular transmission in whom the

differential diagnosis includes LES. It is not recommended for

patients with a past history of, or risk factors for, lung cancer and/or

concurrent neurological symptoms/signs not attributable to LES;

for those situations, order #83380 "Paraneoplastic Autoantibody

Evaluation, Serum." Testing for a newly recognized alternative

antibody of MG (muscle-specific receptor tyrosine kinase) is

indicated when all tests are negative.

See "Myasthenia Gravis /Lambert Eaton Syndrome Diagnostic

Algorithm" in Special Instructions.

Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name

MG/LES Evaluation

Ordering Mnemonic An alternate Mayo code (to the Unit Code) for a test

MGLES

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

Calcium Channel Blockers

Conotoxin (Receptor) Antibodies

Lambert-Eaton Myasthenic Syndrome (LEMS) Antibodies

LEMS (Lambert-Eaton Myasthenic Syndrome) Antibodies

Motor End-Plate Antibody

Motor Nerve Terminal Antibodies

Muscle Culture Antibodies

Muscle End-Plate Antibodies

Myasthenia Gravis Antibodies

Myoid Antibody

Soft-MGLES

Striational (Striated Muscle) Antibodies

VGCC (Voltage-Gated Calcium Channel) Antibodies

Voltage-Gated Calcium Channel (VGCC) Antibodies