What is an ELISA (enzyme-linked immunosorbent assay)?

What is an ELISA (enzyme-linked immunosorbent assay)?

The enzyme-linked immunosorbent assay (commonly called ELISA) is the immunological examination done to measure the antibodies, antigens, proteins and, glycoproteins in biological samples. It is mainly utilized in healthcare, research, and food safety environments for measuring the target chemical components such as hormones, antibodies, and protein biomarkers. This particular test depends on the immunoglobulin (antibodies) to detect the target antigen with the help of highly specific antibody-antigen interactions. It is one of the easiest tests because it is rapid and quick. Moreover, samples routinely used in ELISAs include serum, plasma, saliva, cell culture supernates, urine and tissue lysates.

ELISA assay is performed with the help of 96 well plates, which allows measuring multiple samples in one test. These plates are the special absorbent plates coated with a capture antibody specific for the analysis of interest. Upon incubation, the target analyte is captured by this antibody. Next, a conjugated detection antibody is used to bind to a different epitope on the target analyte to complete the sandwich. A substrate solution is subsequently added to determine the presence and amount of analyte. ELISA test is used for diagnosing HIV infection, pregnancy, zika virus, pernicious anemia, syphilis, rotavirus, coronavirus etc.

The ELISA assay test has been used as a diagnostic tool in the medicinal field, plant pathology, biotechnology, and quality control check in various industries.

Advantages of ELISA tests 

  • This test is often preferred because of its high sensitivity and specificity. ELISA gives more accurate results and diagnosis as compared to any other techniques.
  • It is usually done in 96 well microplate formats. The main advantage of the ELISA test is that 96 determinations can be performed in a single run. You can get results in less than 3 hours. So, it is both quick and efficient for performing immediate analysis without any complex sample pre-treatment.
  • This test does not require radioisotopes or any other costly radiation counters. ELISA test requires accurate micropipettes, an incubator, a washing system, and a microplate spectrophotometer reader.
  • With fully automated ELISA processing systems, various examinations can be done. The fully automated robotic machines for the ELISA test can perform the entire test from start to end. The process can be done up to 15 assays per day shift.
  • ELISA test is considered a flexible tool for all medical professionals and laboratories worldwide because it tests antigens and antibodies.
  • This particular test is eco-friendly and safe because there is no use of any radioactive substance.

 

What are the different types of ELISA antibody tests?

ELISA assay can be done with various modifications based on the basic procedure – direct, indirect, sandwich ELISA test.

  • Direct ELISA – It is the simplest form of ELISA test, which requires antigens to be absorbed on the multi-well plate and then bound by a labeled “detection” antibody. The antigen-coated on the plate is detected by the antibody which are directly associated to an enzyme. As only one antibody is used in a direct ELISA, they are less precise.
  • Indirect ELISA – The indirect ELISA test technique uses a two-step detection process. This test involves two binding processes for primary antibody and labeled secondary antibody. Firstly, an unlabeled primary antibody binds to the specific antigen. Then, an enzyme is joined to the secondary antibody directed against the primary antibody’s host species. This method is highly sensitive because more than one labeled antibody binds to the primary antibody. Indirect ELISA is a more economical procedure than the direct ELISA test. But this test poses a potential risk for cross-reactivity caused by secondary antibody.
  • Sandwich ELISA – Sandwich ELISA or sandwich immunoassay is among the most commonly used testing formats and is done to measure the antigen between 2 layers of antibodies (capture and detection antibody). This test requires combining antibodies to two different epitopes on the target protein for higher specificity. One of the antibodies is immobilized on the surface of the multi-well plate and incubated first with the target protein and then with a specific antibody is added, which is labeled with an enzyme. Thus, facilitating the detection of the antigens. Sandwich ELISA assay is highly sensitive than the direct and indirect ELISA tests. It delivers highly specific results because it uses two antibodies for detecting the antigens. 

The best ELISA test kit by Optofluidic Bioassay – MicroFluere Human Interleukin 6 (IL-6)

Optofluidic Bioassay is proud to offer the best ELISA kit for quantitative measurement of natural and recombinant human Interleukin 6 (IL-6). The ELISA test kit by Optofluidic Bioassay guarantees to give précised, consistent and reliable results. We even generate optimized paired antibodies for the customized sandwich ELISA tests. The ELISA kit contains sufficient materials to run 5 MicroFluere pre-coated 96-well plates. 

 Optofluidic Bioassay MicroFluere Human Interleukin 6 (IL-6) kit comes with a 5-plate MicroFluere pack plus 100 absorbent pads. The MicroFluere plates give 5 to 10 times faster test results, uses five times smaller reagent volume and have a ten times higher dynamic range. Not only this, MicroFluere Plates by Optofluidic Bioassay requires a smaller amount of sample volume for testing. The process for the ELISA test with the help of our MicroFluere kit is faster and requires only ten steps compared to the traditional method, which is a process of a total of 21 steps. You can now use the MicroFluere plates by Optofluidic Bioassay for testing the COVID patients. For more details, contact us at https://www.optobio.com/contact/

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