Difference between Antigen COVID Rapid Tests vs. Antibody COVID Rapid Tests

As Covid-19 rates of infection continue to rise throughout the country, so does Covid testing. In the past nine months, as many of us have changed the way we live our lives, medical research has moved forward at what seems like warp speed.  Today, we have vaccines on the horizon and a host of Covid-19 testing available. Both of these will hopefully help mitigate this illness and allow the country to eventually move forward in a less restrictive way.

While the advances made by the medical community are necessary and welcome, many are often confused when it comes to the options for testing.  In particular, it is critical to understand the differences between Antigen Covid Rapid Tests and Antibody Covid Rapid Tests.  While they sound similar; they are in fact, very different. And, depending upon the situation at hand, one may be significantly more appropriate than the other.

First, it is important to recognize that what the two tests do have in common is that they both offer results quickly, something that is incredibly valuable with a disease that spreads so quickly.

Antigen Covid Rapid Tests

Antigen rapid tests are a tool used to quickly diagnose a current Covid-19 infection.  These tests, administered by a nose or throat swab, can be analyzed in a clinic or a doctor’s office, they do NOT need to be sent to a lab.  Thus, results are available within a short time frame, sometimes in less than an hour. Particularly useful in those who are showing symptoms, these tests are also popular when high frequency testing is being conducted (like in nursing homes, for professional sports teams and in airports, prior to flying).  

Antibody Covid Rapid Tests

On the other hand, Antibody Covid Rapid Tests are used to identify past exposure to and infection from Covid-19.  They are NOT used to test for a current infection.  These tests, administered in a doctor’s office through a finger-prick blood test, often return results in less than 15 minutes. It is important to understand that antibodies are not detectable until several days after infection, but they can remain in a person’s system for months. Some medical professionals recommend waiting until several weeks post-infection to go for this test. People who have antibodies are at a lower risk for reinfection (although we do not know for how long). 

A medical professional is the best person to determine which type of test to administer. If you are feeling ill and looking for results quickly, the Antigen Rapid Test is likely your best choice.  However, if you are concerned you were exposed in the past and want to confirm, an Antibody Test would be helpful.  

In today’s environment, healthcare providers are likely offering a variety of tests and using the results to determine current and future care issues.  These tests not only provide important information to individuals who are or have been sick, but they also are incredibly useful to the communities in which these people live.  Testing helps determine infection rates and implement contact tracing, two important factors in controlling Covid-19.