ARUP's Laboratory Test Directory

RNP (U1) (Ribonucleic Protein) (ENA) Antibody, IgG : 0050470

Mnemonic: RNP

Methodology: Multi-Analyte Fluorescent Detection
Performed: Sun-Sat
Reported: 1-2 days
Specimen Required: Collect:  One 4 mL serum separator tube.

Storage/Transport Temperature:  1 mL serum at 2-8°C. (Min: 0.2 mL)  Submit specimen in an ARUP Standard Transport Tube.

Remarks:  Separate serum from cells ASAP.

Unacceptable Conditions:  Plasma and other body fluids.  Severely lipemic, contaminated, and hemolyzed specimens.

Stability (collection to initiation of testing):  After separation from cells: Ambient: 2 days; 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: RNP antibody is seen in 95-100% of mixed connective tissue disease and is considered specific for this syndrome if other antibodies are negative; RNP is also present in 20-30% of systemic lupus erythematosus and 15-25% of progressive systemic sclerosis.
Note: RNP antigens also contain epitopes which are immunologically identical to free Smith antigens.  The Smith antibody response must be considered when interpreting RNP results.
CPT Code(s): 86235
Cross References: Anti-RNP (ENA) Antibody
 
 

 

 

 
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