ELISA is the acronym for Enzyme- Linked Immuno Sorbent Assay, also known as EIA, and represents the fastest and surest way of diagnosing different infectious diseases in humans, animals and plants. ELISA kits are mostly used in immunology for detecting the presence of antibodies or antigens in samples. The ELISA test is very similar to the way in which an average pregnancy test works.

ELISA kits can also be used in several industries for quality control. For example, the food industry can easily use ELISA kits to detect potential food allergens. Eggs, milk, peanuts or walnuts can be easily detected in any food by simply using this test. Moreover, this test can also be helpful in toxicology. ELISA kits can be rapid screens for certain drugs.

This test can evaluate the presence of both antigen and antibodies in any given sample. Therefore, besides the more commercial use, the ELISA kits are commonly used for detecting HIV or the West Nile Virus, as well as for detecting the presence of antigen.

ELISA kits are very simple to use and the results are immediate. However, the ELISA test needs to be seconded by other tests in some cases. For example if it tests positive for HIV, then it is ninety percent possible that the antibodies are present in your body, but for one hundred percent certainty other tests should be taken.

ELISA kits also have another advantage to other tests available today. The price of such a test is lower than that of other similar products available on the market today. The easy use of the ELISA kits is another selling point, in addition to the accurate results of this test.

An amount of antigen is enclosed to the surface of the plate and then specific antibodies are washed over this surface in order to bind to the unknown antigen. Antibodies are linked to enzymes. In the final step of the test, a certain substance is added in order for the enzymes to be able to convert to a detectable signal. Fluorogenic substrates are generally used, because they produce a very strong visible signal. The results of an ELISA test are reported as numbers.

ELISA kits have numerous uses. Besides screening for HIV, detecting the presence of antigen or using this kit in food industries to detect allergens, the ELISA kits are also appropriate for monitoring the progress of patients once they have started treatment.

The sensitivity of an ELISA test can be compared to experienced microscopic examinations, without having to observe intact organisms. Although the performances of the ELISA test are significant, there are certain limitations. If the test is nonreactive, you might still be exposed to a pathogen, but in an early stage, where the exposure is difficult to determine.

However, the majority of tests based on detecting antibodies or antigen may prove to be unreliable during the early stage of exposure. Of all these tests, the ELISA kit has proven to be the most reliable, which is the reason why it is one of the most used test kits in the world.