We answer common questions each week about the coronavirus crisis. Send us an email at firstname.lastname@example.org if you have any questions. The subject line should be: “Weekly Coronavirus Question.” You can find an archive of our FAQs right here.
My local drugstore now offers antibody testing. Do I have to pay a fee to find out how protected I am against COVID?
Although there are more antibody tests available, unfortunately the answer is no. Experts answered this question. They explained why serology tests, also known as antibody tests, are not useful for most people and why you shouldn’t change any of your behavior based upon the results.
First, some background. A COVID antibody measures one part of your body’s immune reaction to the vaccine or virus. An antibody test does not determine whether you have COVID, unlike PCR tests or the often difficult-to-find rapid antibodies.
Cynthia Leifer, a Cornell University professor in the Department of Microbiology and Immunology, says that “it absolutely cannot tell” if you are [currently] infected.
Antibody tests are blood tests that analyze a sample from your blood to determine if your immune system is able to mount one type of defense against infection with the SARS virus-coV-2 vaccine or not. The test measures the amount of antibodies in your blood. A positive result means that you have likely been exposed to the virus or vaccine. If your result is negative, it could indicate that you have not been exposed to the vaccine or virus.
The idea of an immunity passport that was based on antibody levels appeared promising at the beginning of the pandemic. However, the question that everyone wants to answer is “Am I protected?” Leifer states that an antibody test is not a good option.
Leifer says there are many reasons for this.
She also says that the required amount of antibodies for protection varies between people. A study of 1,497 Israeli health care workers that was fully vaccinated has shown a correlation between higher levels antibodies and greater protection. However, it is impossible to determine how many antibodies are sufficient.
Leifer also points out that not all antibodies are created equal. IGM antibodies are released by the body at the first sign that you have been exposed. Then, your body switches to IGGs which are more effective in protecting you against viral diseases such as COVID-19. Your level of protection could be affected if you have too many of one type of antibodies but not enough of the other. Most tests don’t show the difference, and even those that do tell you can only be marginally more helpful since there is no standard threshold for determining how protected you are.
Antibodies are not the only thing that will protect you against COVID. When activated by a virus or vaccine, T-cells that attack infected cell cells will also help you. This response is not currently measured by any current tests. (Plus, the immune system has another arm that helps to clear the virus.
A positive test is a simple way to find out if you have had the vaccine. This shouldn’t surprise anyone! Or if you have been exposed, but not how protected. Even if you don’t have the vaccine, you may still be tempted to get an antibody test to check if you are infected. However, this doesn’t guarantee that you won’t become infected again. No matter what the outcome, public health agencies recommend that you get vaccinated.
The FDA has approved dozens of antibodies tests to help identify people who may have an adaptive immune response against SARS-CoV-2. However, the FDA doesn’t recommend these tests as a way to test your immunity.
Is there a potential use for an anti-body test?
Baker and Leifer agree that these tests can prove to be extremely useful in studying the entire population. Baker says that antibody tests can be used to help researchers determine how many of the virus is present. She adds that researchers use antibodies to determine how long antibodies can last. This could be useful in helping scientists decide the best timing and amount of booster shots. Antibody tests are being used in research right now.
Baker suggests that you contact your doctor if you believe an antibody test may be helpful for your personal health. Ask your doctor or pharmacist which test they offer, and then go to the FDA website to find out if it gives you specific results or a general “positive”/”negative” result.
If you want to find out if your COVID has been diagnosed, Baker believes that an antibody test may give you a more meaningful result when more information is available about your protection. You’re likely out of luck for now.