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24800 MuSK Antibody (MUSK)

MuSK Antibody (MUSK)
Test Code: MUSKSO
Synonyms/Keywords
​Muscle Specific Receptor Tyrosine Kinase
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
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​Serum ​Red Top Tube (RTT) Serum Separator Tube (SST)​ 1.5 mL 1.0 mL​ ​
Collection Processing Instructions
​Collection date is required.
Specimen Stability Information
Specimen Type Temperature Time
Serum​ ​ ​Ambient 72 hours
​Refrigerated (preferred) 28 days​
​Frozen ​28 days
Interference
​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.
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories Tuesday and Thursday 3 days
Radioimmunoassay (RIA)​
Reference Lab
Mayo Clinic Laboratories
Reference Range Information
< or = 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.
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​83519 ​ ​
Synonyms/Keywords
​Muscle Specific Receptor Tyrosine Kinase
Ordering Applications
Ordering Application Description
​Centricity ​MuSK Antibody (470)
​Cerner ​MuSK Quant Titers Antibody (482)
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
​Serum ​Red Top Tube (RTT) Serum Separator Tube (SST)​ 1.5 mL 1.0 mL​ ​
Collection Processing
​Collection date is required.
Specimen Stability Information
Specimen Type Temperature Time
Serum​ ​ ​Ambient 72 hours
​Refrigerated (preferred) 28 days​
​Frozen ​28 days
Interference
​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.
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
Reference Range Information
< or = 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.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Mayo Medical Laboratories Tuesday and Thursday 3 days
Radioimmunoassay (RIA)​
Reference Lab
Mayo Clinic Laboratories
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
​83519 ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.