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HelpTest Code MGLE Myasthenia Gravis/Lambert-Eaton Myasthenic Syndrome Evaluation, Serum
Reporting Name
MG/LEMS Evaluation, SPerforming Laboratory
Mayo Clinic Laboratories in Rochester
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
Method Name
ARBI, CCPQ, MUSK: Radioimmunoassay (RIA)
ACMFS: Flow Cytometry
MGLEI: Medical Interpretation
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.
Specimen Type
SerumSpecimen 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 daysTest 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 |
Forms
If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.
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.