ENA Combi ELISA Kit (Extractable Nuclear Antigens)

Full Name: ENA Combi ELISA Kit (Extractable Nuclear Antigens)
Reactivity: Human
Sample Type: Serum, Plasma
Sensitivity: 0.5 U/ml


Extractable nuclear antigens (ENA) are nuclear and soluble cytoplasmic antigens which are associated with connective tissue disorders (CTD). There are over 100 different types, however, the six main antigens which are frequently utilised in immunological laboratories are Sm, Scl-70, Ro, Jo1, La and RNP. These are usually intended to screen for mixed connective disease, systemic lupus erythematosus and Sjögren’s syndrome for example anti-Sm (for SLE), anti-RNP (for MCTD), anti-Ro and anti-La (for Sjögren’s), anti-Jo and anti-Scl70 (for Dermatomyositis).

The specificity and sensitivity obtained using these test will depend largely on the type of assay being employed and therefore vary from on laboratory to another.


Human ENA combi ELISA kit for semi-quantitative detection of IgG extractable nuclear antigens (ENA IgG) in human serum and plasma samples. This assay has a minimum analytical sensitivity limit of 0.5 U/ml.

Purified antigens SS-A (52 and 60 kDa), SS-B, Sm, RNP/Sm, Scl-70 and Jo-1 are bound to individual rows of the microwell plate.


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, highly purified human extractable nuclear antigens bound to microwells.
  • Calibrators A-D: Concentrations 12.5, 25, 50, 100 U/ml, made up from ENA antibodies in a serum/buffer matrix.
  • Sample Buffer (5x).
  • Enzyme Conjugate: Containing anti-human IgG antibodies, HRP labelled.
  • TMB Substrate.
  • Stop Solution: Contains acid.
  • Wash Buffer (50x).
  • Certificate of Analysis.
  • Instruction for use.


The minimum detection sensitivity level of human extractable nuclear antigens (ENA IgG) using current ENA combi ELISA kit was 0.5 U/ml. The dynamic range for this assay is 12.5 – 100.0 U/ml.


– Measuring Range: 0 – 100 U/ml.
– Expected Values: Cut-Off 25 U/ml
– Results Interpretation: Negative: < 25 U/ml, Positive: ≥ 25 U/ml
– Sensitivity: <0.055 ng/ml
– Linearity: 94 – 103%
– Limit Of Detection (LOD): 1 U/ml
– Intra Assay Precision: 2.0 – 4.0%
– Inter Assay Precision: 2.5 – 4.3%
– Interfering Substances: None
– Clinical Diagnosis: Sensitivity (93.1%), Specificity (97.6%), Overall agreement (96.1%).


  1. Autoantibodies to extractable nuclear antigens: making detection and interpretation more meaningful. Clin Diagn Lab Immunol. (2002) 9 (1): 1-7. Review. Phan T.G., et al.
  2. From ANA to ENA: how to proceed? Autoimmun Rev. (2006) 5 (1): 10-7. Review. Damoiseaux J.G. and Tervaert J.W.
  3. Serum antinuclear and extractable nuclear antigen antibody prevalence and associated morbidity and mortality in the general population over 15 years. Autoimmun Rev. (2016) 15 (2): 162-6. Review. Selmi C., et al.
  4. The use of laboratory tests in diagnosis and monitoring of systemic lupus erythematosus. J Nephrol. (2002) 15 Suppl 6: S20-7. Review. Sinico R.A., et al.
  5. Antibodies targeting extractable nuclear antigens: historical development and current knowledge. Br J Dermatol. (2001) 145 (6): 859-67. Review. Wenzel J., et al.


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