Antigen vs. Antibody Testing: What’s the Difference?

MD Medical Group is now offering both Antigen Testing for rapid COVID-19 detection and Antibody Testing at select locations!*

Antigen vs. Antibody Testing: What’s the Difference?

 

Antigen Testing

This test is designed to identify the people who are currently infected with the COVID-19 virus, but it’s not to be confused with the nose swab genetic test, which initially diagnoses the disease.

How does it work? This test is conducted by collecting a patient’s sample from a swab to the throat, where the virus likes to hang out, this test is similar to a strep rapid test that is done at any doctor’s office. This test looks for proteins that come from the COVID-19 virus that are called antigens. This type of test can be considered as a more straight forward rapid genetic test.

How accurate is this test? Quidel Corp. got an emergency granted FDA approval on May 8th, 2020 for their antigen test. Many researchers and medical professionals have expressed that they do not expect the antigen test to be as accurate as the PCR diagnostic test. The test itself is about 85% sensitive, which means that in a group of 100 people who currently have coronavirus, only about 85 of them will test positive.

 How long does it take? The new recently FDA approved test by Quidel Corp. usually takes around 15 minutes to process and deliver the results. The rapidness of the test allows medical professionals to screen may people in family clinics or hospitals to determine if someone is currently at high risk of spreading the COVID-19 virus.

For this test, it’s important for patients to remember to follow up with a PCR diagnostic test to make a proper medical diagnosis.

 

Antibody Testing

This test is used to identify those who have already been infected and have recovered from the COVID-19 virus. This test is not used to determine if a person is currently infected.

How does it work? This blood test looks for the development of antibodies against the coronavirus as a result of being infected with the virus. The antibodies are generally produced anywhere from 4 days up to 2 weeks after a patient is first infected; whether there are symptoms or not, there should be evidence of the presence of antibodies fighting against the virus. The test is conducted by taking a small finger prick sample of a patient’s blood.

How accurate is this test? This test serves as a good measure of infection rates in different parts of the country. The Food and Drug Administration (FDA) initially allowed these tests to be sold without an FDA approval, but they have recently tightened their guidelines due to the high numbers of different tests being distributed on the market today and their lack of accuracy, the most popular one being the finger prick test.

These tests are not good predictors of whether or not a person is safe to go back to work or anywhere of the sort due to the fact that some people do not develop antibodies and it cannot be determined if they are immune or not, they do however serve as a tool to determine how many people were infected in the first place.

How long does it take? The antibody test can produce results in under an hour. The most popular test (finger prick), usually produces its results in 15 minutes, whereas more sophisticated tests (which are less widely available) can take up to around an hour, due to their higher accuracy rate.

 

*For more information on locations, please visit https://mdmedicalgroup.us/drive-thru-testing-for-covid-19-dfw-locations/ to find out more.

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