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https://asm.org/Articles/2020/August/How-the-SARS-CoV-2-EUA-Antigen-Tests-Work
Yesterday, I explained the basics of the PCR test and in today’s article, I would like to describe the COVID-19 antigen testing technology. Antigen testing is not a new technology, and has been used to detect respiratory illnesses in the past including strep throat. There are currently two methods of testing for the COVID-19 antigen test including the three laboratory assay methods and the lateral flow model that can be purchased at a store and used at home. The antigen testing technology has strengths and weaknesses, and will be utilized for more diseases, as it has been used in the past.
COVID-19 is a respiratory illness that manifests itself in the nasal cavities before moving to the lungs. Antigen testing is used for rapid respiratory illness assessment, and unlike the PCR test, do not involve the amplification of a small sample volume. The antigen test for COVID-19 uses one of three tests called assays that detects a protein on the surface of the virus called the N-protein. This method involves the use of specific laboratory testing equipment. The lateral flow system uses a testing “card” and swab. The swab is inserted into the nose and then placed into a hole in the “card”. Like the laboratory assay mode, the lateral flow system detects the viral N-protein and communicates the result visually. The “card” liner has COVID-19 antibodies that cling onto the N-antigen, which is shown to the tester. There are currently three lateral flow tests approved for use that work in a similar fashion. Each test should take 10-15 minutes to use and this method costs significantly less than a PCR.
Antigen tests are generally less accurate and may produce false positives at a higher rate than PCR tests. Antigen testing quick, cheaper than PCR and easy to use and understand. Antigen tests for COVID-19 use a swab to collect material in the nasal cavities, so if a patient is asymptomatic and does not have a proliferation of the virus in the nose a false negative may occur. The combination of both laboratory assay antigen testing and lateral flow (at-home or in-clinic) testing allows for quicker and cheaper detection of respiratory infections that is in-line with good infection control efforts.
Posted in Hive and Steemit