COVID Antigen Test

According to the Food and Drug Administration (FDA), Antigen COVID-19 tests are designed to test for an active COVID-19 infection, or in other words, are diagnostic tests. These tests detect structures on the outside of the COVID-19 virus, which are known as antigens. Antigens are proteins that make up viruses, which are the precursor to the body’s generation of antibodies. Ultimately, the test uses lab-made antibodies to search for any antigens that may be present.

Historically, antigen testing has been used to diagnose respiratory pathogens including the flu virus. Most recently, it was given emergency use authorization by the FDAto test for COVID-19.

Antigen tests are immunoassays, which are tests that measure the presence of a small molecule in a solution. They are authorized to be performed on the nasopharyngeal, nasal, or saliva specimens. Antigen tests are similar to polymerase chain reaction (PCR) tests and other nucleic acid amplification tests (NAATs) but are considered to be less sensitive. Most people use antigen tests because they are easy and quick, typically producing results within 15 to 30 minutes, when used in accordance with the relevant instructions.

According to the Centers for Disease Control (CDC), you should get an antigen test if you believe you have been exposed to COVID-19, if you don’t have access to a PCR test, and if you are wanting a quick testing option that will give you fast results. Most often, antigen tests are used as a screening mechanism for COVID-19, rather than a diagnostic test, as they are not as reliable when compared to PCR testing.

The CDC notes that additional reasons for people to consider getting an antigen test include:

• If you are needing to screen large groups of people such as those living within nursing homes, dorms, homeless shelters, correctional facilities, universities, or other like environments.
• If you are undergoing surgery and need to ensure that you are not carrying an active infection.

According to the CDC there is an algorithm that is used for antigen testing in community settings:

• If a person presents as asymptomatic and has a positive antigen test, the conclusion is that there is enough evidence to assume that person is infected with COVID-19 and should isolate following the CDC’s guidelines.
• If a person is asymptomatic, gets a negative antigen test, and has not had close contact with someone who has had COVID, they do not need to quarantine. If a person tests negative, has had close contact with someone who has COVID-19, and is up to date on their vaccines, they also do not have to isolate. If they are not up to date on their vaccines and have been exposed to someone who is positive, it is recommended that they isolate for at least 5 days and follow precautions through day 10.
• If someone is symptomatic and has a negative antigen test, they should get a follow-up PCR or NAAT test. If these secondary tests are negative and they have not had close contact with someone who tests positive and/or are updated on their vaccines, they likely do not have COVID-19.

If someone is symptomatic, tests negative on the antigen test, has had close contact with someone who tests positive, and is not up to date on their vaccines, that person should quarantine for at least 5 days and follow precaution for 10 days.

COVID-19 antigen tests are generally widely available throughout the country, however, an individual’s access will vary depending on their geographical location, particularly during peak infection periods. Ultimately, if you are interested in getting an antigen test completed, reach out to a healthcare provider, who can likely point you in the right direction.

The CDC notes that many people use the antigen tests out of convenience and because they can easily be completed in the comfort of your own home. If possible, having several antigen tests at home is ideal, allowing for testing when needed. Most insurance plans will reimburse up to 8 tests per month, whether they are bought all at once or at different times.

You can also have an antigen test completed at a local pharmacy or lab, depending on where you live. At this point, tests are likely free or completely covered by insurance. In addition, many companies are providing free tests for employers.

If you haven’t undergone the experience of getting an antigen test, it can be helpful to know what you are going into ahead of time so that you can be best prepared. First, there are no steps needed or considerations to be made prior to taking a test.

During the test, a sample is first treated with a liquid containing salt and soap, which breaks down specific cells and particles. Then, you apply the liquid to a testing strip that has antibodies specific to COVID-19. This means that the antibodies on the test strip will bind to the antigen in the sample if there are any. If the antibodies bind to the antigens, your testing strip will appear with a colored line (usually pink), which indicates that you have an active COVID-19 infection.

Usually, many people self-administer these tests following the directions provided in the kits without any issues. A downside to the antigen test is that, because they are less accurate than a PCR test, there needs to be a larger amount of viral load for a person to get a positive test. If you are in an earlier stage of infection, an antigen at-home test may not be the best choice.

According to the CDC, if you test positive after getting an antigen test completed, you should follow the CDC's guidelines for safely isolating yourself until you recover.

Current quarantine guidelines recommend that if you test positive for COVID-19 you:

• Isolate and take precautions to prevent spreading the sickness to others.
• Wear a high-quality mask if needing to be in public.
• Inform those whom you have been in contact with that you tested positive.
• Monitor your symptoms and seek necessary medical care, if needed.
• Contact your healthcare provider to learn about any treatment options that could be relevant for you.