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Test Code MUSK Muscle-Specific Kinase (MuSK) Autoantibody, Serum

Important Note

Effective 1/12/18

EXPLANATION: To decrease the frequency of test cancellations due to insufficient volume

the minimum volume for MUSK: Muscle-Specific Kinase (MuSK) Autoantibody, Serum is

increasing. The new minimum volume is 1.0 mL.

 

 

 

 

Useful For

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

Reporting Name

MuSK Autoantibody, S

Specimen Type

Serum


Specimen Required


Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 1.5 mL

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


Specimen Minimum Volume

1 mL

Specimen Stability Information

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

Reference Values

≤0.02 nmol/L

Interpretation

A positive result, in the appropriate clinical context, confirms the diagnosis of autoimmune muscle-specific kinase myasthenia gravis.

 

Seropositivity justifies consideration of immunotherapy.

Clinical Reference

1. Li Y, Arora Y, Levin K. Myasthenia gravis: newer therapies offer sustained improvement. Cleve Clin J Med. 2013;80(11):711-721

2. Lennon VA: Serological profile of myasthenia gravis and distinction from the Lambert-Eaton myasthenic syndrome. Neurology 1997;48 (Suppl 5):S23-S27

3. Chan KH, Lachance DH, Harper CM, Lennon VA. Frequency of seronegativity in adult-acquired generalized myasthenia gravis. Muscle Nerve. 2007;36(5):651-658

4. Skjei KL, Lennon VA, Kuntz NL. Muscle specific kinase autoimmune myasthenia gravis in children: A case series. Neuromuscul Disord. 2013;23(11):874-882

Day(s) Performed

Monday through Friday

Report Available

3 to 10 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

86366

LOINC Code Information

Test ID Test Order Name Order LOINC Value
MUSK MuSK Autoantibody, S 51716-9

 

Result ID Test Result Name Result LOINC Value
64277 MuSK Autoantibody, S 51716-9

Method Name

Radioimmunoassay (RIA)

Forms

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-Neurology Specialty Testing Client Test Request (T732)

-General Request (T239)