ELISA Test

Question: Discuss about theELISA Test. Answer: Overview This review aims to describe a rapid diagnostic assay using a Protein Technology. The assay that has been selected is ELISA Test. ELISA refers to Enzyme Linked Immunsorbent Assay. It is a well-known method and is most widely used rapid diagnostic assay. It is typically performed for detecting the presence and/or quantity of a target protein present in an experimental sample. The method of detecting the target protein is made possible through antibodies that make this technique as an immunoassay1. This test has been utilized as a diagnostic tool in the plant pathology and medicine. It is also utilized as a quality-control test in different industries. There are different types of ELISA Test namely, Indirect ELISA, Direct ELISA, Sandwich ELISA and Competitive and Inhibition ELISA. It is an important tool to determine the concentrations of serum antibody and it is a simple, versatile, sensitive and quantitative test. Method ELISA is concerned with the detection of an analyte, which is a specific substance and its presence is analyzed either qualitatively or quantitatively in a liquid medium through a method, which continues to utilize the liquid reagents throughout the analysis. The method of ELISA involves the separation of a number of components of an analytical reaction blend through the adsorption of certain constituents on a solid phase that has been physically immobilized. The addition of a liquid sample is carried on a stationary solid phase having exceptional binding properties and it is followed by numerous liquid reagents, and their addition, incubation and washing is carried out and is followed by a few visual changes such as development of color by the product of the enzymatic reaction 2. (Source: Takwoingi, Leeflang and Deeks. 2013) The sensitivity of process of detection is dependent on the signal amplification in the course of the analytical reactions. The generation of signal takes place by the enzymes that are linked foe detecting the reagents in fixed quantities. This is the reason, why this assay is given the enzyme linked. This test comprises of the components such as coated plates, substrate, conjugate, sample diluent, wash concentrate, controls and stop solution. The equipments of this test comprise of Dilutors, pipettes, ELISA plate readers and washer systems. Some of the other equipments include Incubator and Humidity chamber 3. The first step of this method involves the coating of antibody, in which the immobilization of a specific antibody is carried out on the plates that are meant for binding of a specific protein and is kept for overnight incubation. The blocking of plates is carried out with an unrelated protein such as albumin 7. The second step involves capturing the protein. This step is initiated with the addition of samples as well as standard solutions and their capturing takes place by the bound antibodies. The third step involves the detection of antibody in which the addition of specific biotinylated detection antibody to the wells is carried out for enabling the detection of the protein that has been captured8. In the fourth step, the addition of Streptavidin conjugated with horseradish peroidase (HRP) or alkaline phosphatise carried out and this leads to the binding with the biotinylated antibody. In the next step, addition of colorimetric substrate to the wells is performed and it results i n the formation of a coloured solution when it is catalyzed through the enzyme. In the final step, the analysis is performed by measuring the absorbance in a ELISA reader and the determination of the amount of protein is also carried out 4. (Source: Takwoingi, Leeflang and Deeks. 2013) Usefulness and Cost of the Technology ELISA is useful for detecting the presence of an antigen on antibody within a sample. It plays a significant role for determining the concentrations of serum antibody in a virus test. This test has an important application in the food industry for the detection of allergens in the food products. It is also applied in the situations of outbreak of disease for keeping a track on the spreading of diseases such as STDs, cholera and HIV6. It is also used to detect the antibodies in the blood sample for previous exposure to diseases like trichinosis and Lyme disease. The successful detection of antigens such as pregnancy hormones can be easily carried out by this test. It has proved to be an accurate quantitative method that can be used for the serodiagnosis of toxoplasmosis. The tests of ELISA are usually inexpensive and the companies that manufacture the test kits keep a low-cost for the customers 5. It is performed for detecting the presence and/or quantity of a target protein present i n an experimental sample. The method of detecting the target protein is made possible through antibodies that make this technique as an immunoassay. It has been utilized as a diagnostic tool in the plant pathology and medicine. It is also utilized as a quality-control test in different industries (Source: Takwoingi, Leeflang and Deeks. 2013) Comparison with DNA or other Technologies The ELISA test is different with DNA and other technologies as ELISA is a test which is used for detecting the presence of proteins in a sample, instead of DNA i.e. this test cannot be used for the detection of DNA 4. On the other hand, the tests like Southern blotting; Recombinant DNA technology is utilized for detecting DNA in animal or plant sample. DNA technology involves a set of diverse techniques, which allows the researchers foe examining, changing and creating new genetic substance. It ranges from the identification of criminals, creation of new biological products and involves the work of individuals from diverse disciplines. It also helps to understand the mechanisms of life, to solve mysteries and crimes and create solutions for nutrition along with healthy. Therefore, it differs largely in comparison to the ELISA test 6. To sum up, the ELISA test is a simple and a rapid diagnostic assay and offers a variety of advantages over the other techniques that are used in proteomics or protein technology in an efficient manner. Therefore, it plays a significant role and has varied applications that makes it a choice by the scientists and researchers. References Heick J, Fischer M, Kerbach S, Tamm U, Popping B. Application of a liquid chromatography tandem mass spectrometry method for the simultaneous detection of seven allergenic foods in flour and bread and comparison of the method with commercially available ELISA test kits. 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