This test checks for a type of antibody called immunoglobulin G (IgG) that is the result of past or recent exposure to COVID-19, also known as the novel coronavirus. The human body produces IgG antibodies as part of the immune response to the virus. It usually takes around 10 to 18 days to produce enough antibodies to be detected in the blood.

Test results may help identify if you were previously exposed to the virus and, if exposed, can check whether or not your body has produced antibodies. Antibodies typically suggest protective immunity after you’ve recovered or been exposed to COVID-19. However, evidence is still being collected to determine if IgG antibodies provide protective immunity against SARS-CoV-2, the virus that causes COVID-19 infection.

  • If you were never diagnosed with COVID-19, this test can help determine if you may have been previously exposed to the virus.
  • If you were diagnosed with COVID-19, this test can check whether or not your body has produced antibodies.

Multiple sources, including the CDC and healthcare experts, recommend you discuss your test results and whether to return to work with your healthcare provider and employer.

This test may be helpful if you:

  • Have had a positive test for COVID-19 and it has been at least 7 days and you want to know if you have detectable levels of IgG antibodies
  • Have not experienced a fever or felt feverish in the last 3 days
  • Have not experienced new or worsening symptoms of COVID-19 in the past 10 days: loss of smell or taste, shortness of breath or difficulty breathing, feeling weak or lethargic, lightheadedness or dizziness, vomiting or diarrhea, slurred speech, and/or seizures

This test may NOT be helpful if you are:

  • Feeling sick or have had a fever within the last 3 full days, please contact a healthcare provider
  • Trying to diagnose COVID-19, please contact a healthcare provider
  • Less than 7 days since being tested for and diagnosed with COVID-19
  • Directly exposed to COVID-19 in the past 14 days
  • A person with a compromised immune system, a condition that makes it difficult to fight infections

Note: This test can sometimes detect antibodies from other coronaviruses, which can cause a false positive result if you have been previously diagnosed with or exposed to other types of coronaviruses. Additionally, if you test too soon, your body may not have produced enough IgG antibodies to be detected by the test yet, which can lead to a false negative result.

At this time, antibody testing is mainly used in studies to determine how much of the population has been exposed to COVID-19. There is not enough evidence at this time to suggest that people who have IgG antibodies are protected against future COVID-19 infection. Positive or negative antibody tests do not rule out the possibility of COVID-19 infection. Results also do not provide any information on whether you can spread the virus,