Blood samples are analyzed to identify specific proteins and their concentrations using the ELISA method.
The ELISA method is a test used in immunology and other scientific fields to detect antibodies and antigens. ELISA stands for enzyme-linked immunosorbent assay, which refers to the fact that enzyme-coupled antibodies are used to determine test results. The ELISA method is used in medicine to detect antibodies against diseases as a diagnostic measure, and is a common technique used in immunological and biochemical research.
Exposure to body fluids during mouth-to-mouth resuscitation and the CPR process can expose people to HIV.
The ELISA test was developed in the 1960s and 1970s to replace the immunological test that involved the use of radioactive antibodies and antigens. The risks of using radioactive materials made the testing process cumbersome and unsafe, and the advent of the ELISA method solved both problems. Instead of using radioactive materials to determine test results, ELISA uses enzymes that react with antibodies to form colored products. Color development in an ELISA test indicates a positive result.
Receiving a blood transfusion can inadvertently expose a person to HIV.
There are several different types of ELISA tests. The most widely used ELISA method is called indirect ELISA; this is an antibody test used to determine if a certain type of antibody is present in a sample and in what concentration. In diagnostic medicine, this test is used to detect the presence of antibodies against infectious diseases such as HIV, hepatitis, and others. The presence of antibodies against these diseases indicates that the tested individual has been exposed to the infectious agents. Typically, the sample used is blood from a patient.
The ELISA test is commonly used to detect signs of exposure to HIV.
In this test, a specific antigenic protein is used to coat a microtiter plate. This small plastic plate contains 96 tiny wells and a single ELISA test can be performed on each well. The antigen used for a particular test depends on the type of antibody the test is trying to detect. For example, if the ELISA is used for an HIV test, the antigen used will be specific for that virus.
An indirect ELISA is used to determine if a particular type of antibody is present in a sample and at what concentration.
As the test progresses, small amounts of the unknown sample are added to each well of the microtiter plate and the plate is incubated to allow the antibodies in the sample to bind to the antigen. A secondary detection antibody is then added to each well of the plate. If the sample contains any of the antibody types being tested, it will bind to the secondary detection antibody during the subsequent incubation period.
If the HIV antibody test is positive, the diagnosis should be confirmed by viral load testing.
The key to the ELISA method is that the secondary antibody is labeled with a specific type of enzyme. The enzyme used can change the color of the test sample when it reacts with its substrate. Therefore, if a sample contains any of the antibodies being tested, adding substrate to a well will cause it to change color due to the presence of the secondary antibody and its associated enzyme.
The ELISA method is a test used in immunology to detect antibodies and antigens.
There are other variations on the ELISA method, including a test called a sandwich ELISA. This is used to detect antigens in a sample, rather than antibodies. In this test, the microtiter plate is coated with a standardized sample of antibody. Next, the antigen test sample is added, followed by the addition of the secondary detection antibody and its associated enzyme. As with indirect ELISA, the formation of a colored product indicates a positive result.