Muscle-Specific Kinase (MUSK) Autonatibody, Serum

Message

Sendout, Mayo test code: MUSK

Test Code

LAB234007

Alias/See Also

MUSK

CPT Codes
83519

Preferred Specimen

1.5 mL serum from a red tube

Minimum Volume

1 mL

Other Acceptable Specimens

Serum gel tube

Instructions

Centrifuge and aliquot serum into a plastic vial.

Transport Container

Plastic vial

Transport Temperature

Refrigerated

Specimen Stability

Refrigerated (preferred): 28 days
Frozen: 28 days
Ambient: 72 hours

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Gross hemolysis: Reject
Gross lipemia: Reject
Gross icterus: Reject

Methodology
Radioimmunoassay (RIA)

FDA Status
Approved

Setup Schedule

Monday through Friday

Report Available

5-10 days

Limitations

Immunosuppressant therapy is a common cause of false-seronegativity. It is, therefore, important to perform a comprehensive serological evaluation before initiating immunosuppressant therapy.

Interpretation of a patient's serological and clinical status is further complicated when characteristic signs of myasthenia gravis are obscured by a superimposed steroid-induced myopathy.

Reference Range

Included with report

Clinical Significance

Diagnosis of autoimmune muscle-specific kinase (MuSK) myasthenia gravis

Second-order test to aid in the diagnosis of autoimmune myasthenia gravis when first-line serologic tests are negative

Establishing a quantitative baseline value for MuSK antibodies that allows comparison with future levels if weakness is worsening

Performing Laboratory
Mayo Clinic Laboratories, Rochester, Minnesota

Additional Information
Muscle-Specific Kinase (MuSK) Autoantibody, Serum

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.