Sign in →

Test Code NMS1 Necrotizing Myopathy Evaluation, Serum


Ordering Guidance


Before ordering this test, assess the probability of the patient having immune-mediated necrotizing myopathy by using the Immune-mediated necrotizing myopathy calculator.



Necessary Information


Provide the following information:

-Relevant clinical information

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



Specimen Required


Collection Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Submission Container/Tube: Plastic vial

Specimen Volume: 3 mL

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


Useful For

Evaluating patients with suspected necrotizing autoimmune myopathy

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

A thorough understanding of a patient’s history, along with clinical examination and laboratory testing, are needed for a clinico-sero-pathological diagnosis of immune-mediated necrotizing myopathy (IMNM). To assess the probability of your patient having IMNM, see the Immune-mediated necrotizing myopathy calculator.

 

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

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

Serum

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

Reject Due To

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus Reject

Reference Values

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

<20.0 CU

 

Signal Recognition Particle Antibody Screen:

Negative

 

Signal Recognition Particle Antibody:

Negative

 

Signal Recognition Particle Antibody, Titer:

<1:240

Interpretation

Seropositivity for 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) or signal recognition protein (SRP) autoantibodies supports the clinical diagnosis of necrotizing autoimmune myopathy (NAM). A paraneoplastic basis should be considered, according to age, sex, and other risk factors. In cases of NAM, immune therapy is required and often multiple simultaneously utilized immunotherapies are needed to successfully treat patients.

Day(s) Performed

Tuesday, Thursday

 

Report Available

10 to 14 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

86255

82397

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

Reflex Tests

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

Forms

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