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Smith and RNP (U1) (ENA) Antibodies, IgG
3000460
Ordering Recommendation

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.

Mnemonic
SMITH_RNP
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 (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
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
Test Number
Components
Reference Interval
0050470RNP (U1) (Ribonucleic Protein) (ENA) Antibody, IgG
29 AU/mL or lessNegative
30-40 AU/mLEquivocal
41 AU/mL or greaterPositive

0050085Smith (ENA) Antibody, IgG
29 AU/mL or lessNegative
30-40 AU/mLEquivocal
41 AU/mL or greaterPositive


Interpretive Data
Refer to report.

Note
Hotline History
View Hotline History
Components
Component Test Code*Component Chart NameLOINC
0050085Smith (ENA) Antibody, IgG18323-6
0050470Ribonucleic Protein (U1) (ENA) Ab, IgG33983-8
* 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 U1RNP
  • Anti-Ribonucleic Protein
  • Anti-RNP (ENA) Antibody
  • Anti-Sm
  • Anti-Smith (ENA) Antibody
  • Sm antibody IgG
  • Sm/RNP
  • Sm/RNP Antibody
  • U1 RNP