What is Elisa?

The enzyme immunosorbent test (ELISA) is a common test used in immunology to detect antigens or antibodies. Antigens evoke the reaction of the immune system - in other words they cause diseases. Elisa is used to detect many bacterial and viral antigens, including a virus of human immunodeficiency (HIV), malaria, cholera, measles and mumps. A slightly different elisa protocol can be used to detect antibodies to these and many other pathogens. The ELISA protocol is a progress of a gradual step to perform specific Elisa.

Although the ELISA protocol differs slightly, depending on the type of ELISA, the basic concept is the same for all of them. Elisa depends on the antibodies linked to the enzyme, also called antiglobulins . The signal molecule connected to these antiglobulins causes color to change during the test if the desired antigen or antibody is present. The amount of antigen or antibodies present is proportional to the amount of color that can be measured using the electron readeronic plates.

There are three main types of Elisa. And direct Elisa is usually used to detect antigens rather than antibodies. This is the simplest ELISA protocol because the enzyme antibody binds directly to the required antigen. The substrate is then added to determine the amount of antigen present.

Indirect Elisa is used to detect antibodies, while another type of indirect Elisa can be used to detect antigens - called sandwich Elis. The ELISA sandwich protocol requires two antibodies called antibodies to capture and detect to bind to the desired antigen. Antiglobulin is added that binds to the detection antibody and adds the substrate. The indirect Elisa monitors a similar protocol, but uses a capture antigen rather than a catching antibody to detect a desired antibody.

Competitive Elisa is often used to detect antigenes that are present at low concentrations because it is a very sensitive test. Unlike the other protocols, Elisa uses a competing Elisa instead of an antibody and a slightly different quantification method. In it, a sample containing the antigen to be detected, and the enzyme -bound antigen is added to the antibody and two antigens competitions for places binding antibody. When adding the substrate, the change in color is larger, with a higher ratio of bound enzyme -bound antigens to binding sampling antigens. This means that a higher color change is detected at lower concentrations of the sample antigen, which is what makes this method so sensitive.