Evaluating patients with signs and symptoms of a connective tissue disease in whom the test for antinuclear antibodies is positive
Testing for RNP antibodies is not useful in patients without demonstrable antinuclear antibodies.
For more information see Connective Tissue Disease Cascade.
Multiplex Flow Immunoassay
Anti U1RNP
Anti-Ribonuclear Protein
Anti-RNP (Anti-Ribonucleoprotein)
Anti-SmRNP
Anti-U1RNP (Anti-Ribonucleoprotein)
Autoantibodies to U1RNP
Ribonucleoprotein (RNP) Autoantibodies
SmRNP Autoantibodies
U1RNP (Ribonucleoprotein) Autoantibodies
For more information see Connective Tissue Disease Cascade.
Serum
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
0.35 mL
Gross hemolysis | Reject |
Gross lipemia | Reject |
Gross icterus | OK |
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Serum | Refrigerated (preferred) | 21 days | |
Frozen | 21 days |
Evaluating patients with signs and symptoms of a connective tissue disease in whom the test for antinuclear antibodies is positive
Testing for RNP antibodies is not useful in patients without demonstrable antinuclear antibodies.
For more information see Connective Tissue Disease Cascade.
RNP (also called nRNP and U1RNP) is a small nuclear ribonucleoprotein that contains 3 protein autoantigens (called A, C, and 68 kD). Sera that contain RNP antibodies react predominately with the A and 68-kD autoantigens. Antibodies to RNP occur in approximately 50% of patients with lupus erythematosus (LE) and in patients with other connective tissue diseases, notably mixed connective tissue disease (MCTD). MCTD is characterized by high levels of RNP antibodies without detectable Sm (Smith) or double-stranded DNA (dsDNA) antibodies. MCTD resembles LE but is not accompanied by renal involvement.(1,2)
RNP is 1 of 4 autoantigens commonly referred to as extractable nuclear antigens (ENA). The other ENAs are SS-A/Ro, SS-B/La, and Sm. Each ENA is composed of 1 or more proteins associated with small nuclear RNA species (snRNP) ranging in size from 80 to approximately 350 nucleotides. Antibodies to ENAs are common in patients with connective tissue diseases (systemic rheumatic diseases) including LE, MCTD, Sjogren syndrome, scleroderma (systemic sclerosis), and polymyositis/dermatomyositis.
For more information see Connective Tissue Disease Cascade.
<1.0 U (negative
> or =1.0 U (positive
Reference values apply to all ages.
A positive result for RNP antibodies is consistent with a connective
1. Homburger H, Larsen S: Detection of specific antibodies. In
2. Kotzin B, West S: Systemic lupus erythematosus. In Clinical
Recombinant RNP-68 and RNP-A antigens are bound to polystyrene microspheres, which are impregnated with fluorescent dyes to create a unique fluorescent signature. RNP antibodies, if present in diluted serum, bind to the RNP antigens on the microspheres. The microspheres are washed to remove extraneous serum proteins. Phycoerythrin (PE)-conjugated antihuman IgG antibody is then added to detect IgG anti-RNP bound to the microspheres. The microspheres are washed to remove unbound conjugate, and bound conjugate is detected by laser photometry. A primary laser reveals the fluorescent signature of each microsphere to distinguish it from microspheres that are labeled with other antigens, and a secondary laser reveals the level of PE fluorescence associated with each microsphere. Results are calculated by comparing the median fluorescence response for RNP microspheres to a 4-point calibration curve.(Package insert: Bioplex 2200 ANA Screen. Bio-Rad Laboratories, Hercules, CA 11/2011)
Monday through Saturday
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.
86235
Test Id | Test Order Name | Order LOINC Value |
---|---|---|
RNP | RNP Ab, IgG, S | 29958-6 |
Result Id | Test Result Name |
Result LOINC Value
Applies only to results expressed in units of measure originally reported by the performing laboratory. These values do not apply to results that are converted to other units of measure.
|
---|---|---|
RNP | RNP Ab, IgG, S | 29958-6 |