Myasthenia Gravis Lambert-Eaton Syndrome Evaluation (Sendout)

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.

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.

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.

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.