RNP 70 Ab ELISA Kit (Ribonucleoprotein 70)

Full Name: RNP 70 Ab ELISA Kit (Ribonucleoprotein 70)
Reactivity: Human
Sample Type: Plasma, Serum
Sensitivity: 1.0 U/ml


Autoantibodies directed against ribonucleoprotein 70 (RNP-70) have been important for the serological detection of Sharp syndrome (MCTD – Mixed Connective Tissue Disease), it is essentially a 70kDa protein which is part of the U1-snRNP complex. The sensitivity of this is 100%, meaning that MCTD can be completely ruled out if the autoantibodies are absent. However, some patients with SLE and systemic sclerosis are also found to test positive for anti-RNP. In general, patients only displaying antinuclear antibodies against the this protein tend to have the classical MCTD, whereas, other SLE-typical autoantibodies (for example anti-Sm, dsDNA and anti-histone) are found this indicates transition into SLE. Anti-RNP are antinuclear antibodies which belong to the extractable nuclear antigen antibodies (ENA) subset and these are directed against the U1-ribonucleoprotein of the ribonucleoprotein multi-enzyme complex.


Human RNP 70 Ab ELISA kit is intended for measuring in-vitro quantitative levels of IgG autoantibodies to ribonucleoprotein 70 (RNP-70, anti-RNP 70, RNP-70 Ab) in human serum or plasma samples. This assay has a minimum analytical sensitivity limit of 1.0 U/ml.


All reagents supplied need to be stored at 2 °C – 8 °C, unopened reagents will retain reactivity until expiration date. Do not use reagents beyond this date.

  • Divisible Microplate: Consisting of 12 modules of 8 wells, purified RNP-70 is bound to microwells.
  • Calibrator A-F: Concentrations 0, 12.5, 25, 50, 100, 200 U/ml, made up from ribonucleoprotein 70.
  • Control Positive and Control Negative: Containing human anti-RNP 70 antibodies in a serum/buffer matrix.
  • Sample Buffer (5x).
  • Enzyme Conjugate: Contains anti-human IgG antibodies, HRP labelled.
  • Substrate: 3,3’, 5,5’- Tetramethylbenzidin (TMB).
  • Stop Solution.
  • Wash Buffer (50x).
  • Certificate of Analysis.
  • Instruction for Use.


The minimum detection sensitivity level of human IgG antibody to ribonucleoprotein 70 (RNP-70 IgG, RNP 70 Ab) using current RNP-70 Ab ELISA kit was 1.0 U/ml. The dynamic range for this assay is 12.5 – 200.0 U/ml.


– Limit Of Detection (LOD): Functional sensitivity was 1 U/ml.
– Measuring Range: 0 – 200 U/ml
– Linearity: 97 – 100%
– Expected Values: Cut-off 25 U/ml.
– Results Interpretation: Negative: < 25 U/ml, Positive: ≥ 25 U/ml.
– Intra Assay Precision: 3.9 – 5.8%
– Inter Assay Precision: 4.9 – 5.2%
– Interference: None.
– Clinical Diagnosis: Sensitivity (66.0%), Specificity (95.8%), Overall agreement (82.3%).


  1. Autoantibody recognition of distinctly modified forms of the U1-70-kd antigen is associated with different clinical disease manifestations. Arthritis Rheum. (2000) 43 (4): 881-8. Greidinger E.L., et al.
  2. Identification of human Sm and (U1) RNP antigens by immunoblotting. J Immunol Methods. (1983) 64 (1-2): 45-59. Guldner H.H., et al.
  3. Human autoantibodies against the 70-kd polypeptide of U1 small nuclear RNP are associated with HLA-DR4 among connective tissue disease patients. Arthritis Rheum. (1990) 33 (5): 666-73. Hoffman R.W., et al.
  4. Anti-Sm and anti-RNP antibodies. Autoimmunity. (2005) 38 (1): 47-54. Review. Migliorini P., et al.
  5. T cell vaccination therapy in an induced model of anti-RNP autoimmune glomerulonephritis. Clin Immunol. (2010) 137 (2): 281-7. Trivedi S., et al.


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