RNP Antibodies, IgG, Serum
Use
Evaluating patients with signs and symptoms of a connective tissue disease in whom the test for antinuclear antibodies is positive. Antibodies to U1 ribonucleoprotein particle (U1-RNP) are central to the diagnosis of mixed connective tissue disease and are also associated with other antinuclear antibody (ANA)-associated connective tissue diseases such as systemic lupus erythematosus, systemic sclerosis, undifferentiated CTD, and CTD overlap syndromes. Testing for ribonucleoprotein particle antibodies is not useful in patients without demonstrable antinuclear antibodies.
Special Instructions
For more information see Connective Tissue Disease Cascade: https://www.mayocliniclabs.com/it-mmfiles/connective_tissue_disease_cascade.pdf.
Limitations
The U1 ribonucleoprotein particle (RNP) 68/A antibody is more sensitive than the Sm (Smith)/RNP antibody test. Low positive results (<=4.0 U) without an associated positive antinuclear antibodies by indirect immunofluorescence assay should be interpreted with caution. This test detects antibodies to both RNP68 and RNPA proteins. Combined response is more sensitive and less specific than assays to the Sm/RNP.
FDA ApprovedNew York Approved
Methodology
Immunoassay (Multiplex Flow Immunoassay)
Biomarkers
LOINC Codes
- 29958-6
- 29958-6
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
0.5 mL
Minimum Volume
0.35 mL
Container
Plastic vial
Collection Instructions
Centrifuge and aliquot serum into a plastic vial. Preferred collection container is a serum gel tube, but a red top tube is also acceptable.
Causes for Rejection
Gross hemolysis, Gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Refrigerated | 21 days |
| Frozen | 21 days |