Myasthenia Gravis Lambert-Eaton Syndrome Evaluation (Sendout)

General Information

Lab Name

Myasthenia Grav_LES Evl (Sendout)

Lab Code

RMGLEG

Epic Name

Myasthenia Grav_LES Evl, (Sendout)

External Test Id

MGLE

Description

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
For a complete list of tests and potential reflex tests included in this panel, refer to the Testing Algorithm section on Mayo's Clinical & Interpretive page: Myasthenia Gravis/Lambert Eaton Syndrome.

Synonyms

ACh Receptor (Muscle) Binding Ab, MG_LES Evaluation, MGLE, Myasthenia Gravis Antibody Panel, P/Q-Type Calcium Channel Ab

Components

Code	Name
RCCPQ	P/Q Type Calcium Channel Ab
RACHRM	ACh Receptor (Muscle) Binding Antibody (Sendout)
RMGINT	Myasthenia Gravis_LES Interp

Interpretation

Method

Radioimmunoassay (RIA): P/Q-Type Calcium Channel Antibody, ACh Receptor (Muscle) Binding Antibody, MuSK Autoantibody (Reflex only)
Flow Cytometry: AChR Modulating Flow Cytometry

Reference Range

See individual components

Interferences and Limitations

Cautions:

Specimens should be collected prior to administration of immunosuppressant therapy as this may reduce the diagnostic sensitivity of the assay; the neurological diagnosis is further confounded if steroid myopathy develops.

These results should only be interpreted in the appropriate clinical and electrophysiological context and are not diagnostic in isolation.

Positive muscle acetylcholine receptor (AChR) may occur in autoimmune liver disorders and in patients with graft-versus-host disease and recipients of D-penicillamine.

Weakly positive results may occur with hypergammaglobulinemia and should be interpreted with caution in the appropriate clinical context.

AChR modulating antibodies will only be performed if AChR binding antibodies are present or if there is an interfering substance present that precludes testing for AChR binding antibodies.

Seropositive rates and quantitative results differ across laboratories and patient results tested at different laboratories should not be treated equivalently.

The presence of alpha-bungarotoxin antibodies may interfere with the AChR muscle binding antibody assay and therefore if detected, AChR binding results will not be reported.

Ordering & Collection

Specimen Type: Blood
Collection: 9 mL blood in RED TOP tubes or GOLD SST
Handling Instructions: Outside Laboratories: Centrifuge sample and transfer serum to a separate plastic vial. Refrigerate serum while awaiting shipment. Transport with a cold pack.

Stability: Refrigerated (Preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Reject Due To: Gross hemolysis, lipemia, icterus.
Quantity: Requested: 3 mL serum
Minimum: 2 mL serum

Processing

Receiving Instructions

Centrifuge sample and transfer serum to a separate plastic vial. Refrigerate serum.

Sendouts:

Order Mayo Test: MGLE
Interfaced: Yes [Interface: 601; Worksheet: MARF]

Stability: Refrigerated (preferred): 28 days; Frozen: 28 days; Ambient: 72 hours.

Reject Due To: Gross hemolysis, lipemia, icterus.

Misc Sendout

Performance

Lab Department

Sendouts Mayo Lab (RF)(MARF)

Frequency

Performed: Monday through Sunday (profile tests only; reflex test days vary). Reported: 3-10 days from sample receipt at Mayo Clinic Laboratories.

Available STAT?

Performing Location(s)

Sendout	Mayo Clinic Laboratories 800-533-1710 200 First Street Southwest Rochester, MN 55901

Billing & Coding

CPT Codes: 86041, 86596
LOINC: 55397-4
Interfaced Order Code: UOW2347
Billing Comments: Reflex testing may be performed at additional cost.