Antigen Test for COVID-19

How is it Different from Corona Virus Testing?

A year struggling with COVID-19 and still end is nowhere to be seen. It seems like we are digging the hole deeper. Cases are increasing and so is the need for testing. Testing is also a very important ammunition against the pandemic. It is not lost on anyone that COVID-19 testing has been an expensive and time-consuming method. So, other methods to test the presence of the COVID-19 virus have been continuously researched and Antigen is one such method.

What is Antigen?

The antigen is a substance that can stimulate the body to produce an immune response by activating lymphocytes which are white blood cells that are the main infection-fighting cells of the body. Antigens are of different types and can be found in the form of proteins, lipids, polysaccharides, or nucleic acids. The immune system of the body recognizes the distinctive features present on the surface of the antigens.

What is Antigen testing?

Antigen testing is a diagnostic point-of-care nasopharyngeal swab test that indicates presence or absence of COVID antigen in the body. It takes 30 min to test. The test is crafted to detect a certain protein in the virus that stimulates the immune response in the body.

How does antigen work?

COVID-19 has many known antigens like nucleocapsid phosphoprotein, a glycoprotein that has a spike-like protrusion o its surface. Antigens produce antibodies that have Y- shaped proteins produced by B cells of the immune system. These Y- shaped proteins have antigen-binding sites that bind to the specific part of the antigen surface.

This process helps in eliminating antigens from the body by direct neutralization or by pushing them for elimination by other arms of the immune system.

What does the antigen test indicate?

Whether a person is currently infected by any pathogens virus in this case that is the SARS-CoV-2 virus. The nucleic acid-based test detects genetic materials whereas antigen testing detects proteins, glycans. These proteins are found on the surface of the SARS-CoV-2.

How will the antigen test help in detecting COVID-19?

Antigen tests are generally used to diagnose the presence of respiratory pathogens like influenza, or respiratory syncytial virus. The antigen test detects the presence of a viral antigen that implies a current infection. Rapid Antigen Test for COVID-19 is a test picks on the traces of any antigens in the body which indicates the presence of a virus in recent time.

In simple words, the Rapid Antigen test detects the presence of viral proteins that occur in the body if the body is subjected to the COVID-19 virus. It is generally tested in a sample taken from the respiratory tract. If the antigens are present in a certain quantity it will attach itself to specific antibodies on the paper strip in an observatory bag which generates visible signals in nearly 30 minutes.

How accurate is the antigen test?

Accuracy of antigen tests depends on the circumstance for and in which they are used. Rapid antigen test gives the best results when conducted in the early stages of infection. In the early stage, the viral virus concentration is high and can be easily detected. Antigen tests are very specific but do have lower sensitivity than the RT-PCR test, reason that the Antigen test is mostly used in the early stages.

This accounts for highly accurate results but chances of picking false negatives. Negative results are not necessarily a confirmation of not being infected. So, a follow-up of the RT-PCR test is necessary to confirm the negative test. Antigen test can be very helpful in controlling the spread as it is a very time-saving test and give results faster.

Antigen tests can help in the control of spread from an actively infectious person.

The antigen test gives results in no tie compared to the RT-PCR test which takes a minimum of 3 days to get the results.

The antigen test is also very cost-effective compared to the very expensive RT-PCR test. If new manufacturers enter the market with an antigen test kit it can lead to an increase in the tests per day rate due to its simple design.

The antigen test is very simple compared to the other genetic test.

Antigen testing can be very helpful due to the increasing number of cases to be tested and a shortage of resources and laboratories to be tested.

Where will the antigen test be helpful?

Although FDA has not given a complete reign over conducting antigen tests it is authorized and with further research, it can be deemed fit to carry on a large scale. In high containment zone antigen tests can help detect influenza-like illness.

COVID hotspots areas can hugely benefit from the fast and quick antigen test to keep the new cases in check but under strict supervision.

Asymptomatic patients can be tested by antigen test. Patients who are already hospitalized for one or the other serious diseases like HIV+, Chemotherapy patients, transplant patients, patients of the age of more than 65.