Useful in confirming a diagnosis of systemic lupus erythematosus (SLE) or mixed connective tissue disease (MCTD) following a positive ANA result. Antibodies may be useful in the differential diagnosis of other systemic autoimmune rheumatic diseases such as systemic sclerosis, Sjögren syndrome, polymyositis, dermatomyositis, and overlap syndromes.
- Patient Preparation
- Serum Separator Tube (SST).
- Specimen Preparation
- Separate from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube. (Min: 0.2 mL)
- Storage/Transport Temperature
- Unacceptable Conditions
- Plasma or other body fluids. Contaminated, hemolyzed, or severely lipemic specimens.
- After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)
|Component Test Code*||Component Chart Name||LOINC|
|0050085||Smith (ENA) Antibody, IgG||18323-6|
|0050470||Smith/RNP (ENA) Ab, IgG||33983-8|
- Anti-Smith (ENA) Antibody
- Sm antibody IgG
- Sm/RNP Antibody