SARS-CoV-2 (COVID-19) Antibody Testing
About COVID-19 Antibody Testing
- Antibody tests for COVID-19 are not useful for diagnosing a current infection.
- The antibody tests for COVID-19 are new and the meaning of the results is not yet fully understood.
- A positive test may not mean that you had COVID-19. The antibody test may detect antibodies to a different Coronavirus (the common cold) or simply be inaccurate (“false positive”)
- It is still not known whether having these antibodies means that you are protected from future infection with COVID-19.
- A negative test does not mean that you have not been exposed to the virus or that you are not infectious.
Frequently Asked Questions
What if the antibody test is positive?
A positive test means you may have been exposed to SARS-CoV2, the virus causing COVID-19. Some tests may detect other common viruses or a positive may simply be a “false positive”. If you have had an illness with symptoms similar to COVID-19 symptoms, a positive test is more likely to be correct.
If I have antibodies to SARS-CoV-2, does that mean that I will not get COVID-19 in the future?
We do not yet know which antibodies protect against COVID-19. A positive test does not necessarily mean that you have any protection against future infection.
Does everyone who is sick with COVID-19 make antibodies to the virus causing COVID-19?
No. Not all people make antibodies to the virus. A small number of people do not make antibodies. Some of these people have weaker immune systems, some have normal immune systems and had very mild symptoms of COVID-19.
Are all tests for antibodies the same?
No. There is a wider range of tests currently being offered. Different tests are not equally good at detecting antibodies. The FDA has been issuing Emergency Use Authorization to test companies. This means the usual rigor testing by FDA has not been done. Companies and laboratories are evaluating the tests prior to offering them to patients. There is wide variability.
Is there any value in getting this test?
Talk with your provider to help answer this question. Currently, there is limited value in getting the test since we don’t know how accurate it is in telling you what most people want to know: Am I protected from COVID-19? If you get the test and it shows no antibodies, then it is likely you are NOT protected, and it is recommended to continue to follow physical distancing guidelines. If you get the test and it does show antibodies, it is still not known if you are protected from COVID-19 and it is recommended you follow the same physical distancing guidelines. If you have had prior symptoms of COVID-19 infection > 21 days ago, the test may be more accurate for you. If you have NOT had symptoms of COVID-19 infection, a test showing you have antibodies may be inaccurate.
It is important to understand that no matter your test results, the same physical distancing guidelines are recommended.
What do major public health organizations recommend regarding antibody testing?
- World Health Organization: There is currently no evidence that people who have recovered from COVID-19 and have antibodies are protected…
- The Washington State Department of Health: Antibody tests are not recommended to reliably determine whether or not someone has experienced a past infection with COVID-19
- CDC: Test for Past Immunity (Antibody Test)
- Infectious Diseases Society of America: IDSA COVID-19 Antibody Primer
- King County Public Health: We don’t know enough about whether a positive antibody test indicates protection to make recommendations at this time. No one should draw definite conclusions about their protection from COVID-19 based on currently available tests.