First and the most basic test for HIV is ELISA. It is the acronym for Enzyme-Linked Immunosorbant Assay. ELISA test is a biochemical treatment which is done to detect the antibodies or antigen in the body. It is also known as Enzyme Immuno Assay or EIA. Previously the HIV test was done with the help of radio immunoassay in which radioactive waves were used to detect the antibodies or antigens. But later on, due to the harmful effects of its radiations the scientist decided to find an alternative for it. This gave rise to ELISA, which is now very widely used as the primary test for HIV. Let's find out the procedure and accuracy for HIV ELISA test.
Types of ELISA Tests
ELISA tests for HIV are of five types. Any one can be used for the detection of HIV. Though they have the same concept, the methods differ in the constituents or the enzymes used. Following are the types of ELISA which are performed for the test of HIV.
- Direct ELISA
- Indirect ELISA
- Sandwich ELISA
- Competitive ELISA
- Multiplex ELISA
The basic mechanism for all these methods is the same. The antibody antigen bonding helps in the detection of the HIV. The antibodies are the result of the immune system which are generated to fight with the antigens. Find out in the procedure how ELISA test helps in the detection of HIV.
ELISA Test Procedure
ELISA test is the basic test for HIV. It help in the detection of the HIV antibodies which are generated to fight against the HIV. This test is conducted in a pathology lab. ELISA test is performed on 8 cm x 12 cm plastic plate. This plate contains an 8 x 12 matrix of 96 wells. Following are the steps which will help you to understand this procedure properly.
Elisa Test Accuracy
- Blood sample of a person is collected which is then processed to get the serum.
- Purified inactive antigens are taken in an ELISA plate.
- The serum collected from the person is then applied on the ELISA plate containing antigens.
- If the person is affected by HIV, his serum should contain its antibodies. Hence, when the serum is applied to the antigen plate, the antibodies will attach to the antigens.
- The slide is then washed with a solution which helps in the removal of other particles except the antigens and the antibodies attached to it.
- Then it is treated with an enzyme. This enzyme gets attached to the antibodies of the antigens and a chemical reaction takes place which results in color change. This color change shows a positive result of HIV.
Elisa Test results are many a time controversial. There may be positive results for the person who may not have HIV. This may be possible with the people who have antibodies for the human leukocyte antigens (HLA). It may be observed in the women who possess multiple pregnancies. This doubt should be removed by taking the further HIV tests which are used to confirm the HIV. The false result may take place between the window of the infection and the antibody response towards the virus. Find out more in HIV window period
. If the ELISA test is reported negative, then no test is conducted further as it is confirmed negative. But if the ELISA test comes positive then it is done few more times to make sure that the sample is positive. If still the test are coming positive, then the sample is further sent for the Western blot test. This test is expensive but it is more accurate than the ELISA test. If the Western blot test shows the result positive, then the person is no doubt HIV positive.
Although ELISA test is surrounded by controversies, it is considered as one of the most accurate tests for HIV. It is capable of detecting even the very early symptoms of HIV. ELISA test is quite inexpensive as compared to the other tests. So, people undergoing this test can trust it. In case, if they get the test positive they should go for the further confirmatory tests and start with the AIDS vaccines as soon as possible.