ARUP's Laboratory Test Directory
| 0050470: RNP (U1) (Ribonucleic Protein) (ENA) Antibody, IgG |
| Test Mnemonic: RNP | |
|
Methodology: Multi-Analyte Fluorescent Detection
Performed: Sun-Sat Reported: 1-2 days |
| Specimen Required: | |
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Collect: One 4 mL SST.
Transport: 1 mL serum at 2-8°C. (Min: 0.5 mL) Submit specimen in an ARUP Standard Transport Tube. Pediatric Collection/Transport: 0.15 mL serum at 2-8°C. Remarks: Separate serum from cells ASAP. Unacceptable Conditions: Plasma and other body fluids. Severely lipemic, contaminated, and hemolyzed specimens. Stability: After separation from cells: Ambient: 2 days; Refrigerated: 2 weeks; Frozen: 1 year (avoid repeated freeze/thaw cycles) |
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| Reference Interval: |
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29 AU/mL or less: Negative 30-40 AU/mL: Equivocal 41 AU/mL or greater: Positive |
| Interpretive Data: | |
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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.
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| 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 |