Sign in →

Test Code LAB0002322 Myasthenia Gravis/Lambert-Eaton Myasthenic Syndrome Evaluation, Serum

Additional Codes

Mayo Test ID
MGLE


Ordering Guidance


This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. The specific waiting period before specimen collection will depend on the isotope administered, the dose given, and the clearance rate in the individual patient. Specimens will be screened for radioactivity prior to analysis. Radioactive specimens received in the laboratory will be held for 1 week and assayed if sufficiently decayed or canceled if radioactivity remains.



Specimen Required


Patient Preparation: For optimal antibody detection, specimen collection is recommended prior to initiation of immunosuppressant medication.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 3 mL

Collection Instructions: Centrifuge and aliquot serum into a plastic vial.


Useful For

Confirming the autoimmune basis of a defect in neuromuscular transmission (eg, myasthenia gravis [MG], Lambert-Eaton myasthenic syndrome [LEMS])

 

Distinguishing LEMS from autoimmune forms of MG

 

Providing a quantitative autoantibody baseline for future comparisons in monitoring a patient's clinical course and response to immunomodulatory treatment

Profile Information

Test ID Reporting Name Available Separately Always Performed
MGLEI MG Lambert-Eaton Interpretation, S No Yes
ARBI ACh Receptor (Muscle) Binding Ab Yes Yes
CCPQ P/Q-Type Calcium Channel Ab No Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
ACMFS AChR Modulating Flow Cytometry, S No No
MUSK MuSK Autoantibody, S Yes No

Testing Algorithm

If acetylcholine receptor (AChR)-binding antibodies are greater than 0.02 nmol/L, then AChR muscle modulating antibody will be performed at an additional charge.

 

If AChR-binding antibodies are 0.02 nmol/L or less, then muscle-specific kinase (MuSK) autoantibody will be performed at an additional charge.

 

If unable to report AChR binding antibody due to interfering substances, then AChR muscle modulating antibody will be performed at an additional charge.

 

If unable to report AChR binding antibody due to interfering substances and AChR muscle modulating antibody is negative, MuSK autoantibody will be performed at an additional charge.

Method Name

ARBI, CCPQ, MUSK: Radioimmunoassay (RIA)

ACMFS: Flow Cytometry

MGLEI: Medical Interpretation

Reporting Name

MG/LEMS Evaluation, S

Specimen Type

Serum

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 28 days
  Frozen  28 days
  Ambient  72 hours

Reject Due To

Gross Hemolysis Reject
Gross lipemia Reject
Gross Icterus Reject

Reference Values

Test ID

Reporting name

Methodology

Reference value

MGLEI

MG Lambert-Eaton Interpretation, S

Interpretation

NA

ARBI

ACh Receptor (Muscle) Binding Ab

Radioimmunoassay (RIA)

≤0.02 nmol/L

CCPQ

P/Q-Type Calcium Channel Ab

RIA

≤0.02 nmol/L

Reflex Information:

Test ID

Reporting name

Methodology

Reference value

ACMFS

AChR Modulating Flow Cytometry, S

Flow cytometry

Negative

MUSK

MuSK Autoantibody, S

RIA

≤0.02 nmol/L

Interpretation

Positive results in this antibody evaluation are indicative of an autoimmune neuromuscular junction disorder. These results should be interpreted in the appropriate clinical and electrophysiological context.

 

In the presence of either acetylcholine receptor antibodies or P/Q antibodies, a paraneoplastic basis should be considered with thymoma being the most commonly associated tumor with myasthenia gravis and small cell lung cancer being the most commonly associated cancer with Lambert-Eaton myasthenic syndrome. Currently, muscle-specific kinase antibody positive myasthenia gravis is not associated with a paraneoplastic etiology.

 

Negative results do not exclude the diagnosis of an autoimmune neuromuscular junction disorder. If clinical suspicion remains and symptoms persistent or worsen consider retesting.

Day(s) Performed

Profile tests: Monday through Sunday; Reflex tests: Varies

Report Available

3 to 10 days

Specimen Retention Time

28 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

86041

86596

86043 (if appropriate)

86366 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MGLE MG/LEMS Evaluation, S 97566-4

 

Result ID Test Result Name Result LOINC Value
8338 ACh Receptor (Muscle) Binding Ab 97558-1
81185 P/Q-Type Calcium Channel Ab 94349-8
34273 MG Lambert-Eaton Interpretation, S 69048-7