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ENA Screen ELISA Kit

INTENDED USE

Human ENA screen ELISA kit can be used to screen in-vitro quantitative concentrations IgG auto-antibodies directed against extractable nuclear antigens (ENAs, ENA screen) in human serum and plasma samples. This assay has a minimum analytical sensitivity limit of diagn. 92.7%.

A mixture of purified antigens SS-A 60, SS-A 52, SS-B, Sm, RNP/Sm, Scl 70 and Jo-1 is coated on to microwells.

ENA elisa kits are widely used for detecting and quantifying proteins and antigens in samples. An ENA panel usually consists of a group of 4 or 6 auto antibody tests and can aid in the diagnosis of autoimmune disorders (including rheumatoid arthritis, lupus etc) and disorders such as coeliac disease. The number of tests requires will depend on the health care practitioner’s and patients autoimmunity and needs. This test helps to monitor and diagnose the progression of different autoimmune diseases. Often the immune system can confuses its own tissues and connective fibres (that protect major organs such as the liver, kidneys and joints) as foreign and creates antibodies against its own tissue.

An ENA test panel is usually requested when a person shows signs of an autoimmune disorder. Signs can include protein in the urine, hair loss, joint swelling, fatigue, sensitivity to light, and neurological symptoms.

BACKGROUND

Extractable nuclear antigens (ENA) are predominately associated to connective tissue disorders (CTD) and these are classified as either soluble cytoplasmic or nuclear antigens. Generally there greater than 100 different types that have been identified, however, there are 6 main groups which are frequently used in research laboratories in order to investigate Sjögren’s syndrome, systemic lupus erythematosus (SLE) and mixed connective disease (MCTD). These are anti-La and anti-Ro for Sjögren’s, anti-Scl70 and anti-Jo for Dermatomyositis, anti-Sm for SLE and anti-RNP for MCTD.

Two gel based methods counterimmunoelectrophoresis and double immunodiffusion have been utilised to discover anti-ENAs and how they are linked to their respective diseases. However, both of these procedures require the antigens to be precipitated in order to obtain meaningful results. Other procedures that have been used include western blotting, enzyme linked immunosorbent assay (ELISA) and passive hemagglutination. At present, the ELISA method is the most popular technique for detecting anti-ENAs, this is due to the fact it is quantitative, easy to perform and can be scaled up to generate high volume output. The sensitivity and specificity generated for these procedures will depend on the assay or test that is being carried out and this will vary between each laboratory.

ENA SCREEN ELISA KIT CONTENT

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.
  • Control A (Negative), Control B (Cut-Off), Control C (Positive): Containing ENA antibodies in a serum/buffer matrix.
  • Sample Buffer (5x).
  • Enzyme Conjugate: Contains anti-human IgG antibodies, HRP labelled.
  • TMB Substrate.
  • Stop Solution: Contains acid.
  • Wash Buffer (50x).
  • Instruction for Use.
  • Certificate of Analysis.

SENSITIVITY

The minimum detection sensitivity level of IgG antibodies directed to human extractable nuclear antigens screen (ENAs) using current ENA screen ELISA kit was diagn. 92.7%. The dynamic range for this assay is to a cut-off index 1.0.

ASSAY CHARACTERISTICS

– Extractable Nuclear Antigens Screen (ENA IgG Screen): ELISA
– Expected Values: Cut-Off 1.0
– Results Interpretation: Negative Index: < 1.0, Positive Index ≥ 1.0
– Intra Assay Precision: 1.6 – 6.0%
– Inter Assay Precision: 1.2 – 6.9%
– Interfering Substances: None
– Clinical Diagnosis: Sensitivity (92.7%), Specificity (96.3%), Overall agreement (94.8%).

Contact us for further information regarding shipping and bulk orders, we distribute elisa kits throughout the United Kingdom, Europe, the United States market and globally.

Please note that current guidance and opinion is that antibodies to DNA and ENA antigens won’t be performed on sera negative for antinuclear antibody (AMA).

For Covid-19 resources and information please see: https://www.nhs.uk/conditions/coronavirus-covid-19/

REFERENCES

  1. Efficiency of different strategies to detect autoantibodies to extractable nuclear antigens. J Immunol Methods. (2010) 360 (1-2): 89-95. Almeida González D., et al.
  2. Comparison of two extractable nuclear antigen testing algorithms: ALBIA versus ELISA/line immunoassay. Pathology. (2016) 48 (5): 491-7. Chandratilleke D., et al.
  3. How should a district general hospital immunology service screen for anti-nuclear antibodies? An ‘in-the-field’ audit. Clin Exp Immunol. (2015) 180 (1): 52-7. Hira-Kazal R., et al.
  4. Application of linear discriminant analysis in performance evaluation of extractable nuclear antigen immunoassay systems in the screening and diagnosis of systemic autoimmune rheumatic diseases. Am J Clin Pathol. (2012) 138 (4): 596-603. Pi D., et al.
  5. Diagnostic testing and interpretation of tests for autoimmunity. J Allergy Clin Immunol (2010) 125 (2 Suppl 2):S238-S247.Castro C, Gourley M.
  6. The Statistics Evaluation of Medical Tests for Classification and Prediction. New York, NY, USA: Oxford University Press; (2003). [Google Scholar] Pepe MS.

ADDITIONAL INFORMATION

  • Full Name: ENA Screen ELISA Kit
  • Reactivity: Human
  • Sample Type: Plasma, Serum
  • Sensitivity: Diagn. 92.7%

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