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Test ID NMS1 Necrotizing Myopathy Evaluation, Serum

Necessary Information

Provide the following information:

-Relevant clinical information

-Ordering provider name, phone number, mailing address, and e-mail address

Specimen Required


Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 3 mL

Collection Instructions: Centrifuge within 2 hours of collection and aliquot 2 mL into a plastic vial.

Useful For

Evaluating patients with suspected necrotizing autoimmune myopathy


The utilization of this combinatorial immunoassay provides accuracy and speed in diagnosis of necrotizing autoimmune myopathy (NAM). Early diagnosis facilitates better prognosis through initiation of aggressive immune treatments, typically requiring more than 1 agent, and discontinuation of statin medications. Persons without access to specialty muscle biopsy testing services may be afforded an early diagnosis through application of this testing.


Identification of NAM may indicate the presence of a paraneoplastic disorder.

Profile Information

Test ID Reporting Name Available Separately Always Performed
NSI1 Necrotizing Myopathy Interp, S No Yes
HMGCR HMG-CoA Reductase Ab, S Yes Yes
SRPIS SRP IFA Screen, S No Yes

Testing Algorithm

This focused algorithmic test is designed to achieve high sensitivity for identification of antibodies specific for necrotizing autoimmune myopathy (HMGCOA-IgG and SRP-IgG). This test is unique in the market by having an initial screen for signal recognition particle (SRP) antibodies performed using tissue indirect immunofluorescence, which increases clinical sensitivity as compared to SRP immunoblot methodologies.


If indirect immunofluorescence assay (IFA) pattern suggests signal recognition particle (SRP) antibody, SRP IFA titer and SRP54 immunoblot are performed at an additional charge.


See Necrotizing Myopathy Evaluation in Special Instructions.

Method Name

SRPIS, SRPTS: Indirect Immunofluorescence Assay (IFA)

SRPBS: Immunoblot

HMGCR: Chemiluminescent Assay (CIA)

NSI1: Medical Interpretation

Reporting Name

Necrotizing Myopathy Evaluation, S

Specimen Type


Specimen Minimum Volume

2 mL

Specimen Stability Information

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

Reference Values

3-Hydroxy-3-Methylglutaryl Coenzyme-A (HMG-CoA) Reductase:

<20.0 CU


Signal Recognition Particle Antibody Screen:



Signal Recognition Particle Antibody:



Signal Recognition Particle Antibody, Titer:


Day(s) Performed

Signal Recognition Particle Antibody:

Tuesday, Thursday


Signal Recognition Particle Antibody Screen:

Tuesday, Thursday, Sunday


Signal Recognition Particle Antibody, Titer:

Tuesday, Thursday, Sunday


3-Hydroxy-3-Methylglutaryl Coenzyme-A (HMG-CoA) Reductase:

Monday through Friday

Report Available

10 to 14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed, and its performance characteristics 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



86256 (if appropriate)

84182 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NMS1 Necrotizing Myopathy Evaluation, S 97561-5


Result ID Test Result Name Result LOINC Value
607414 HMG-CoA Reductase Ab, S 93493-5
603543 Necrotizing Myopathy Interp, S 69048-7
603540 SRP IFA Screen, S 97562-3

NY State Approved


Reflex Tests

Test ID Reporting Name Available Separately Always Performed
SRPBS SRP Immunoblot, S No No


If not ordering electronically, complete, print, and send a Neurology Specialty Testing Client Test Request (T732) with the specimen.

Special Instructions