3-Hydroxy-3-Methylglutaryl Coenzyme-A (HMG-CoA) Reductase, Serum
Use
This test is useful for evaluating patients with suspected necrotizing autoimmune myopathy (NAM) by measuring antibodies to 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR). NAM is associated with these autoantibodies, typically presenting with subacute proximal limb muscle weakness and elevated serum creatine kinase levels. Identifying these antibodies supports earlier diagnosis and treatment initiation, potentially prompting searches for underlying malignancies.
Special Instructions
NMS1 / Necrotizing Myopathy Evaluation, Serum is the preferred first tier test for identifying antibodies specific for necrotizing autoimmune myopathy. It includes signal recognition particle antibodies, enhancing clinical sensitivity compared to other methodologies.
Limitations
Negative results do not exclude NAM diagnosis, as only 35% of cases are associated with HMGCR antibodies. Some cases are positive for other autoantibodies or seronegative. Occasionally, HMGCR antibodies are detected in other diseases, warranting a muscle biopsy for confirmation.
FDA ApprovedNew York Approved
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 93493-5
- 93493-5
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
2 mL
Minimum Volume
1 mL
Container
Plastic vial
Collection Instructions
Centrifuge and aliquot serum into a plastic vial.
Causes for Rejection
Gross hemolysis, Gross lipemia, Gross icterus
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 72 hours |
| Refrigerated | 28 days |
| Frozen | 28 days |