Elisa kits are essential and influential in performing Elisa Tests. An Elisa test is carried out to detect soluble molecules such as hormones, proteins, peptides, antibodies, and other small molecules such as vitamins. The results can also be quantified by using antibodies coupled with enzymes. Meanwhile, the following article will look at Elisa kits’ main things you need.
Features of Elisa Kits
To begin with, we will look at the various features of Elisa kits. If you want to buy or use Elisa Kits, it’s essential to consider the following fundamental features.
Assay Format
Elisa Kits are made in different forms. However, you must consider the formant that captures the antigens you require. The Elisa kits capture antigens in two ways; one through absorption of the antigens to the assay plate and, secondly, by capturing them with an antibody found in the assay plate. You have to ensure you get the appropriate format for your tests and acquire suitable kit systems.
Types of Antibodies
It is possible to use polyclonal and monoclonal antibodies in carrying out Elisa kits. However, there are a few factors you have to consider when using either of them. For example, the type of ELISA format you choose will determine the antibody to use. For instance, you can use a polyclonal antibody to capture the antigens in sandwich format and use a monoclonal to detect them.
When using both antibodies, you must ensure that the Elisa kits create a better and adequate space for teaming up. The two antibodies should not compete or interfere during the capturing and detection. Therefore, you have to buy a matched pair to avoid such problems.
Cross-Reactivity and Interference
Interference or antibody cross-reactivity in your experiment can cause it to lose its specificity. The compatibility of antibodies from host animals is one source of cross-reactivity. Even if it is becoming more common to obtain antibodies made from the animal you require, it is still a good idea to check for cross-reactivity. Similarly, knowing what’s in the kit’s buffers is essential if they contain a substance that alters the antigen-antibody interaction and skews results.
Detection
Today, there are many different ways to detect binding in ELISAs, so the first thing you should seek is a kit that uses the detection you require.
How Does The ELISA Kit Work?
Elisa tests can be carried out in different ways. The most common way of using the Elisa kits is using antibodies attached to the solid surface of the kits. The antibody can detect the availability of the molecule in question, such as the bacteria, hormone, or protein. A good example is when testing for pregnancy, the antibody detects the presence of Human chorionic gonadotropin hormone (HCG).
When conducting such tests, urine or blood samples are added to the testing kits where a purified HCG is added. An analysis is done through the detection of the substance of interest. If HCG is detected, fewer linked enzymes will attach to the solid surface containing the antibodies. In addition, other observations, such as the color change of the solution, can be observed.
Types of Elisa Tests
Direct test
In this Elisa test, an enzyme-labeled antibody is used to detect the investigated substance.
Indirect ELISA
The substance under investigation and the primary antibody can react with the enzyme-labeled antibody in this test.
Sandwich ELISA
The Sandwich Elisa test is one of the most popular and commonly used types of Elisa test. When using the sandwich Elisa, the capture antibody and specific antigens are attached to the polystyrene plate then they are then sandwiched with the substrate to be measured.
Competitive Elisa
Competitive Elisa is similar to sandwich Elisa. However, in this, there is an additional competing antibody. This test helps to give high and accurate results.
Basic ELISA Principles
During an Elisa Test, the antigens are immobilized to a solid surface. This can be done directly or through the use of a capture antibody. An Elisa test is performed in a well-defined Elisa kit such as 96- or 384- wells. The antigen extraction from the other components in the sample is made easier by immobilizing the analyses. Because of this, ELISA is one of the most straightforward experiments to run on several samples simultaneously. An ELISA test works on using techniques to identify analyses in biological specimens identified by an antibody. The Elisa test procedure uses the following fundamental principle:
- The coating solution is mainly for absorbing protein to the plate surface.
- Blocking non-specific binding and matrix interferences are reduced by blocking binding sites using a buffer.
- Antibody detection
- Addition of substrate
- Elisa test analysis of the data
ELISA Advantages
- High sensitivity and specificity: Because antibodies are used, ELISAs can detect antigens at the pictogram level in quite a specific way.
- High throughput: commercial ELISA kits are generally in a 96-well plate format. But the assay can be easily adapted to 384-well plates.
- Easy to perform: procedures are simple and easy to follow and require little hands-on time.
- Quantitative: it is possible to quantify the antigens or the molecules in question by determining their concentration.
- Possibility to test various sample types such as urine, saliva, tissues, serum, cellular, and plasma.
Wrapping Up
Elisa Kits have played an essential role in ensuring efficiency in Elisa Test results. In addition, the simplicity of Elisa’s data analysis makes it possible to give accurate and efficient results. Further, the Elisa kits are essential during protein and antibody expression.
