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Muscle-Specific Kinase (MuSK) Antibody, IgG
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Ordering Recommendation
Secondary diagnostic testing for patients with generalized or ocular myasthenia gravis and no detectable antibodies to acetylcholine receptor (AChR).
Mnemonic
Methodology
Quantitative Radioimmunoassay
Performed
Mon, Thu
Reported
2-8 days
New York DOH Approval Status
Specimen Required
One 4 mL Plain Red or Serum Separator Tube (SST).
Separate from cells ASAP or within 2 hours of collection. Transfer 2 mL of serum to an ARUP Standard Transport Tube. (Min: 0.5 mL)
Refrigerated.
Grossly lipemic, icteric, or hemolyzed specimens.
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 month (avoid multiple freeze/thaw cycles)
Reference Interval
| Negative | 0.00-0.03 nmol/L |
| Positive | 0.04 nmol/L or greater |
Interpretive Data
Muscle-specific kinase (MuSK) antibody is found in a subset of patients with myasthenia gravis, primarily those seronegative for muscle acetylcholine receptor (AChR) antibody. Decreasing antibody levels may be associated with therapeutic response; therefore, clinical correlation must be strongly considered. A negative test result does not rule out a diagnosis of myasthenia gravis.
This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.
Analyte Specific Reagent (ASR)
Note
Hotline History
CPT Codes
83519
Components
| Component Test Code* | Component Chart Name | LOINC |
|---|---|---|
| 3001577 | Muscle-Specific Kinase (MuSK) Ab, IgG | 51716-9 |
Aliases
- Muscle-Specific Kinase Antibody by RIA
- Muscle-Specific Receptor Tyrosine Kinase
- MuSK
- MuSK Autoantibody
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