Most of us recall in the early days of the pandemic that we experienced long lines waiting to get tested for Covid. Then we waited several days to get the results. Now there are commercially available antigen tests that you can do at home to see if you might have an active Covid infection. Let’s take a look at the various tests available to check for active Covid infection, prior infection, and response to the vaccine. It can get a little confusing, let us try to explain the differences.

Testing for Acute Covid Infection

There are two types of diagnostic tests, Antigen Covid Test and PCR Covid Test. These are used to diagnose an acute infection and may be performed in a laboratory, at a testing site, or now at home using a home testing kit.

Home Rapid Covid Antigen Testing

At-home COVID antigen tests are a new and inexpensive way to test for an active infection. The FDA issued Emergency Use Authorization (EUA) for 3 home testing kits – Abbott Binax NOW™, Ellume COVID-19 , and Quidel QuickVue®. All three tests require a nasal swab and deliver results in about 15-30 minutes. The tests can be purchased where available at many different pharmacy locations. The Abbott BinaxNOW test kit runs around $24. The Abbott test may be available without charge through the state of Colorado Covid-19 website.

The at-home test kits include 2 tests, which are intended to be used twice over 2-3 days. Clinical trials show that they are 83%-96% accurate at detecting a positive result for individuals experiencing symptoms. It is also important to note that false negatives are possible. A negative result does not completely rule out infection, especially when testing early in the illness.

Covid PCR Testing

Molecular tests detect the genetic material of the virus using a lab technique called polymerase chain reaction (PCR). The PCR Covid test is very accurate and is considered the gold standard by many healthcare facilities. Oftentimes a PCR test is recommended to confirm the validity of the antigen test.

Although there are no home PCR testing kits, there are home-collection kits. These kits allow samples to be collected at home and sent to a lab for analysis using PCR technology. FDA-authorized home collection kits include: empowerDX, DxTerity, Pixel by Labcorp™, and Amazon COVID-19 Test Collection Kit DTC.

Covid Antibody Testing

Antibody tests look for antibodies that have been produced by our immune system in response to the presence of SARS-CoV-2, which is the virus that causes COVID-19. There are two types of antibody tests. One type shows antibodies from a natural infection only. The other shows antibodies generated against the spike protein from either the vaccine or natural infection. Antibody tests are usually performed through the major commercial laboratories and are not intended to diagnose an active Covid infection.

Bottom Line

According to the CDC “self-tests can be used by anyone who is symptomatic regardless of their vaccination status,” and “unvaccinated persons with no COVID-19 symptoms can also use self-tests, especially if they were potentially exposed to someone with COVID-19.”

The convenience of allowing people to easily and safely be tested at home when indicated is a major breakthrough in the fight against Covid.

We suggest obtaining the at-home Covid antigen tests to have on hand in the event you feel the need to be tested.

Note to Our Patients

As a result of the pandemic, our office is experiencing a much higher call volume and workload. We appreciate those of you who understand this and are so supportive. We are actively looking for more help in the office. If you know someone who is interested, click here.

Thanks for your patience and understanding.


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About The Care Group: We promote optimal wellness by providing an individualized, functional medicine approach to address root causes rather than simply treating symptoms. We help patients with a wide range of issues including autoimmune/ inflammatory disease, digestive disorders, hormone imbalances, and mood disorders. To learn more about our practice, click here.

About the Author: Dr. Gerard Guillory, MD is Board Certified in Internal Medicine and has published two books on Irritable Bowel Syndrome (IBS). In 1985, he opened The Care Group, PC. Today, his clinic is a Primary Care facility that is a hybrid of functional and traditional medicine treating patients with digestive disorders, autoimmune disease, and other conditions. You can learn more about Dr. Guillory here.

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