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Test Code NMS1 Necrotizing Myopathy Evaluation, Serum


Necessary Information


Include relevant clinical information, name, phone number, mailing address, and e-mail address (if applicable) of ordering physician.



Specimen Required


Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 3 mL

Collection Instructions: Centrifuge within 2 hours and aliquot 2 mL.


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
HMGES HMG-CoA ELISA, S No Yes
SRPIS SRP IFA Screen, S No Yes

Testing Algorithm

This is a focused algorithmic test 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.

Method Name

SRPIS, SRPTS: Indirect Immunofluorescence Assay (IFA)

SRPBS: Immunoblot

HMGES: Enzyme-Linked Immunosorbent Assay (ELISA)

Reporting Name

Necrotizing Myopathy Evaluation, S

Specimen Type

Serum

Specimen Minimum Volume

2 mL

Specimen Stability Information

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

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross reject

Icterus

Mild OK; Gross reject

Other

NA

Reference Values

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

<20.0 U/mL

 

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) and Time(s) 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

Specimen Retention Time

28 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 U.S. Food and Drug Administration.

CPT Code Information

86255

83516

86256 (if appropriate)

84182 (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NMS1 Necrotizing Myopathy Evaluation, S In Process

 

Result ID Test Result Name Result LOINC Value
603543 Necrotizing Myopathy Interp, S In Process
603540 SRP IFA Screen, S 53010-5
603538 HMG-CoA ELISA, S In Process

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.