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Chemiluminescence kit for the detection of U1RNP antibodies to in human serum or plasma.

Catalog Number: CL-RNP050
Size: 50 tests
Regulatory status: CE IVD
Clinical topic: Immunology & Autoimmune Diseases
Diagnostic panel: Rheumatic Diseases
  • Detection of anti-U1-RNP antibodies, IgG class
  • Evaluating patients with signs and symptoms of a connective tissue disease and positive test for antinuclear antibodies
  • Aid to evaluate patients with signs and symptoms of systemic lupus erythematosus (SLE)
  • Intended for human serum and plasma
  • A mixture of recombinant RNP A, RNP C and RNP 68 antigens is used

The U1-snRNP ribonucleoprotein complex, also known as Sm/RNP complex, belongs to a group of small nuclear ribonucleoproteins. In addition to other proteins and RNAs, the snRNP complex includes three proteins (RNP 68, RNP A and RNP C) specific for a certain type of ribonucleoproteins. The sera that contain RNP antibodies react predominately with the RNP A and RNP 68 kD autoantigens. Antibodies to RNP A and RNP C proteins are cross-reactive with SmB and SmB’ antigens.

Antibodies to U1-RNP occur in approximately 40-50% of patients with systemic lupus erythematosus (SLE). They have lower specificity than anti-Sm antibodies. High titres are highly specific in patients with other connective tissue diseases, particularly mixed connective tissue disease (MCTD, Sharp's syndrome). MCTD is characterized by high levels of RNP antibodies without detectable Sm antibodies or double-stranded DNA (dsDNA). MCTD resembles SLE but is not accompanied by kidney damage.

Antigen Used: A mixture of recombinant RNP A, RNP C and RNP 68 antigens.

Technical specifications

Technical data
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Technical data

Assay stability30 days on board stability / In use stability until the expiration date at storage temperature 2-8 °C
Sample matrix Serum, Plasma
Sample volume10 µL
Measuring range3-320 U/ml
Assay/kit contentReagent Cartridge with specific reagents for the assay, magnetic particles, calibrators
Complementary productsWash buffer, Anchor® Tips, Stackable cuvettes, Trigger solutions

The kits are CE-IVD certified and intended for professional use.


References to CLIA U1RNP

  • Carpintero MF, Martinez L, Fernandez I, Romero AC, Mejia C, Zang YJ, Hoffman RW, Greidinger EL. Diagnosis and risk stratification in patients with anti-RNP autoimmunity. Lupus. 2015 Sep;24(10):1057-66. doi: 10.1177/0961203315575586. Epub 2015 Mar 2. PMID: 25736140; PMCID: PMC4529793.
    See more on PubMed
  • Sapkota B, Al Khalili Y. Mixed Connective Tissue Disease. 2021 Jan 3. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan–. PMID: 31194355.
    See more on PubMed
  • Gunnarsson R, Hetlevik SO, Lilleby V, Molberg Ø. Mixed connective tissue disease. Best Pract Res Clin Rheumatol. 2016 Feb;30(1):95-111. doi: 10.1016/j.berh.2016.03.002. Epub 2016 Apr 12. PMID: 27421219.
    See more on PubMed
  • 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 Jan;75(1):18-24. PMID: 2702772; PMCID: PMC1541873.
    See more on PubMed
  • Dima A, Jurcut C, Baicus C. The impact of anti-U1-RNP positivity: systemic lupus erythematosus versus mixed connective tissue disease. Rheumatol Int. 2018 Jul;38(7):1169-1178. doi: 10.1007/s00296-018-4059-4. Epub 2018 May 23. PMID: 29796907.
    See more on PubMed
  • Tektonidou MG, Anapliotou M, Vlachoyiannopoulos P, Moutsopoulos HM. Presence of systemic autoimmune disorders in patients with autoimmune thyroid diseases. Ann Rheum Dis. 2004 Sep;63(9):1159-61. doi: 10.1136/ard.2004.022624. PMID: 15308528; PMCID: PMC1755126.
    See more on PubMed


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