Necrotizing Autoimmune Myopathy [Test in Focus]

Necrotizing autoimmune myopathy (NAM) is a serious but rare muscle disease strongly associated with autoantibodies to either the protein signal recognition particle (SRP) or the enzyme 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR). NAM typically manifests with subacute proximal limb muscle weakness and persistently elevated serum creatine kinase (CK) concentrations, but slower onsets can occur and complicate diagnosis.

Christopher Klein, M.D., a neurologist at Mayo Clinic, provides an overview of the new necrotizing autoimmune myopathy test available through Mayo Medical Laboratories. He discusses which types of patients should be tested, how this test improves upon previous methods, and what clinical action can be taken from the results of this test.



Necrotizing Myopathy Evaluation, Serum (Mayo ID: NMS1)


When to Order

This test is useful for:

  • Evaluating patients with suspected necrotizing autoimmune myopathy


Specimen Information

Specimen Type: Serum

Container/Tube: Red Top

Acceptable: Serum Gel

Specimen Volume: 3 mL

Collection Instructions: Centrifuge within 2 hours and aliquot 2 mL

Specimen Stability Information: Refrigerated (preferred)


Performance Information

Day(s) and Time(s) Test Performed

  • Signal Recognition Particle Antibody:
    Tuesday, Thursday; 2 p.m.
  • Signal Recognition Particle Antibody Screen:
    Tuesday, Thursday, Sunday; 6 a.m.
  • Signal Recognition Particle Antibody, Titer:
    Tuesday, Thursday, Sunday; 6 a.m.
  • 3-Hydroxy-3-Methylglutaryl Coenzyme-A (HMG-CoA) Reductase:
    Tuesday, Friday; 6 a.m.

Analytic Time
7 days

Alyssa Frank

Alyssa Frank is a Marketing Segment Manager at Mayo Clinic Laboratories. She leads marketing strategies for product management and specialty testing. Alyssa has worked at Mayo Clinic since 2015.