Test Catalog

Test Id : RNP

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RNP Antibodies, IgG, Serum

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Overview

Test Catalog

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluating patients with signs and symptoms of a connective tissue disease in whom the test for antinuclear antibodies is positive

 

Testing for ribonucleoprotein particle antibodies is not useful in patients without demonstrable antinuclear antibodies.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For more information see Connective Tissue Disease Cascade.

Method Name
A short description of the method used to perform the test

Multiplex Flow Immunoassay

NY State Available
Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Reporting Name
Lists a shorter or abbreviated version of the Published Name for a test

RNP Ab, IgG, S

Aliases
Lists additional common names for a test, as an aid in searching

Anti U1RNP

Anti-Ribonuclear Protein

Anti-RNP (Anti-Ribonucleoprotein)

Anti-U1RNP (Anti-Ribonucleoprotein)

Autoantibodies to U1RNP

Ribonucleoprotein (RNP) Autoantibodies

U1RNP (Ribonucleoprotein) Autoantibodies

Anti-RNP68/A

RNP68/A Autoantibodies

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For more information see Connective Tissue Disease Cascade.

Specimen Type
Describes the specimen type validated for testing

Serum

Specimen Required
Defines the optimal specimen required to perform the test and the preferred volume to complete testing

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

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.

Special Instructions
Library of PDFs including pertinent information and forms related to the test

Specimen Minimum Volume
Defines the amount of sample necessary to provide a clinically relevant result as determined by the testing laboratory. The minimum volume is sufficient for one attempt at testing.

0.35 mL

Reject Due To
Identifies specimen types and conditions that may cause the specimen to be rejected

Gross hemolysis Reject
Gross lipemia Reject
Gross icterus OK

Specimen Stability Information
Provides a description of the temperatures required to transport a specimen to the performing laboratory, alternate acceptable temperatures are also included

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
Frozen 21 days

Useful For
Suggests clinical disorders or settings where the test may be helpful

Evaluating patients with signs and symptoms of a connective tissue disease in whom the test for antinuclear antibodies is positive

 

Testing for ribonucleoprotein particle antibodies is not useful in patients without demonstrable antinuclear antibodies.

Testing Algorithm
Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

For more information see Connective Tissue Disease Cascade.

Clinical Information
Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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 (CTDs) such as systemic lupus erythematosus, systemic sclerosis, undifferentiated CTD, and CTD overlap syndromes.(1-5) Immunologic characterization studies suggest that anti-U1RNP antibodies are directed toward both discontinuous and linear epitopes that are either contained in the protein sequence or are post-translationally modified. These antibodies mainly target the RNP68 or RNP70, RNPA (33 kD), and occasionally RNPC (22 kD) proteins.(4-9)

 

Originally described by Mattioli et al (3) by immunodiffusion assay using calf thymus extract, current solid-phase immunoassays now use diverse analytes (purified or recombinant proteins, synthetic peptides of dominant epitopes) of the 3 main proteins (RNP68 or RNP70, RNPA, and RNPC) either singly or in any of the various combinations.(4-10) Because of the use of these different antigens and combinations thereof, the nomenclature, reporting, and interpretation of anti-U1RNP antibodies remain obscure.(10) In the absence of standardized nomenclature for anti-U1-RNP antibody assays, familiarity of the analytes in specific assays and use of Hep-2 substrate by indirect immunofluorescence assay for ANA are required for appropriate interpretation. In addition, low level anti-U1-RNP antibodies in the absence of ANA have a low predictive value for ANA-CTD. The U1-RNP antibody test offered by Mayo Clinic detects antibodies to both RNP68 and RNPA proteins. Combined response is more sensitive and less specific than assays to the Sm (Smith)/RNP.(10)

 

For more information see Connective Tissue Disease Cascade.

Reference Values
Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

<1.0 U (negative)

> or =1.0 U (positive)

Reference values apply to all ages.

Interpretation
Provides information to assist in interpretation of the test results

A positive result for anti-ribonucleoprotein particle 68/A (RNP68/A) antibodies in association with positivity of antinuclear antibodies may be consistent with a diagnosis of connective tissue disease.

Cautions
Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The U1 ribonucleoprotein particle (RNP) 68/A antibody is more sensitive than the Sm (Smith)/RNP antibody test. Low positive results (< or =4.0 U) without an associated positive antinuclear antibodies by indirect immunofluorescence assay should be interpreted with caution.

Clinical Reference
Recommendations for in-depth reading of a clinical nature

1. Tanaka Y, Kuwana M, Fujii T, et al. 2019 Diagnostic criteria for mixed connective tissue disease (MCTD): From the Japan research committee of the ministry of health, labor, and welfare for systemic autoimmune diseases. Mod Rheumatol. 2021;31(1):29-33

2. Hoffmann-Vold AM, Gunnarsson R, Garen T, Midtvedt O, Molberg O. Performance of the 2013 American College of Rheumatology/European League Against Rheumatism Classification Criteria for Systemic Sclerosis (SSc) in large, well-defined cohorts of SSc and mixed connective tissue disease. J Rheumatol. 2015;42(1):60-63

3. Mattioli M, Reichlin M. Characterization of a soluble nuclear ribonucleoprotein antigen reactive with SLE sera. J Immunol. 1971;107(5):1281-1290

4. Combe B, Rucheton M, Graafland H, Lussiez V, Brunel C, Sany J. Clinical significance of anti-RNP and anti-Sm autoantibodies as determined by immunoblotting and immunoprecipitation in sera from patients with connective tissue diseases. Clin Exp Immunol. 1989;75(1):18–24

5. Ihn H, Yamane K, Yazawa N, et al. Distribution and antigen specificity of anti-U1RNP antibodies in patients with systemic sclerosis. Clin Exp Immunol. 1999;117(2):383-387

6. Pattersson I, Wang G, Smith EI, et al. The use of immunoblotting and immunoprecipitation of (U) small nuclear ribonucleoproteins in the analysis of sera of patients with mixed connective tissue disease and systemic lupus erythematosus: across-sectional, longitudinal study. Arthritis Rheum. 1986;29(8): 986-996

7. Satoh M, Krzyszczak ME, Li Y, et al. Frequent coexistence of anti-topoisomerase I and anti-U1RNP autoantibodies in African American patients associated with mild skin involvement: a retrospective clinical study. Arthritis Res Ther. 2011;13(3):R73

8. Betteridge Z, Tansley S, Shaddick G, et al. Frequency, mutual exclusivity and clinical associations of myositis autoantibodies in a combined European cohort of idiopathic inflammatory myopathy patients. J Autoimmun. 2019;101:48-55

9. Tebo AE, Peterson LK, Snyder MR, Lebiedz-Odrobina D. Clinical Significance of Anti-U1 Ribonucleoprotein Antibody Is Analyte Dependent: Implications for Laboratory Reporting, Interpretation, and Interassay Correlations. Arch Pathol Lab Med. 2023;147(12):1461-1465

Method Description
Describes how the test is performed and provides a method-specific reference

Recombinant ribonucleoprotein particle (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; 02/2019)

PDF Report
Indicates whether the report includes an additional document with charts, images or other enriched information

No

Day(s) Performed
Outlines the days the test is performed. This field reflects the day that the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time before the test is performed. Some tests are listed as continuously performed, which means that assays are performed multiple times during the day.

Monday through Saturday

Report Available
The interval of time (receipt of sample at Mayo Clinic Laboratories to results available) taking into account standard setup days and weekends. The first day is the time that it typically takes for a result to be available. The last day is the time it might take, accounting for any necessary repeated testing.

1 to 3 days

Specimen Retention Time
Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

14 days

Performing Laboratory Location
Indicates the location of the laboratory that performs the test

Rochester

Fees :
Several factors determine the fee charged to perform a test. Contact your U.S. or International Regional Manager for information about establishing a fee schedule or to learn more about resources to optimize test selection.

  • Authorized users can sign in to Test Prices for detailed fee information.
  • Clients without access to Test Prices can contact Customer Service 24 hours a day, seven days a week.
  • Prospective clients should contact their account representative. For assistance, contact Customer Service.

Test Classification
Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR) product.

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.

CPT Code Information
Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Clinic Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.

CPT codes are provided by the performing laboratory.

86235

LOINC® Information
Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the order and results codes of this test. LOINC values are provided by the performing laboratory.

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

Test Setup Resources

Setup Files
Test setup information contains test file definition details to support order and result interfacing between Mayo Clinic Laboratories and your Laboratory Information System.

Excel | Pdf

Sample Reports
Normal and Abnormal sample reports are provided as references for report appearance.

Normal Reports | Abnormal Reports

SI Sample Reports
International System (SI) of Unit reports are provided for a limited number of tests. These reports are intended for international account use and are only available through MayoLINK accounts that have been defined to receive them.

SI Normal Reports | SI Abnormal Reports