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Smith (ENA) Antibody, IgG
0050085
Ordering Recommendation

Confirmatory test for systemic lupus erythematosus (SLE) based on ANA results.

Mnemonic
SMITH
Methodology
Semi-Quantitative Multiplex Bead Assay
Performed
Sun-Sat
Reported
1-2 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
 
Collect
Serum separator tube.  
Specimen Preparation
Separate serum 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
Refrigerated.  
Unacceptable Conditions
Plasma or other body fluids. Contaminated, hemolyzed, or severely lipemic specimens.  
Remarks
 
Stability
After separation from cells: Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles)  
Reference Interval
29 AU/mL or less: Negative
30-40 AU/mL: Equivocal
41 AU/mL or greater: Positive
Interpretive Data
Smith antibody is very specific for systemic lupus erythematosus (SLE) but only occurs in 30-35% of SLE cases. The presence of antibodies to Smith is often associated with renal disease.


Note
CPT Code(s)
86235
Components
Component Test Code*Component Chart NameLOINC
0050085Smith (ENA) Antibody, IgG18323-6
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Anti-Sm
  • Anti-Smith (ENA) Antibody
  • Sm antibody IgG
  • Sm/RNP