Antibodies are large Y-shaped proteins that are produced by the immune system to identify and neutralize foreign objects like viruses. Each antibody has a unique target known as the antigen present on the invading organism. This antigen is like a key that helps the antibody in identifying the organism. Just like every lock has a single key, an antibody has a single antigen key. When the key is inserted into the lock, the antibody activates, tagging or neutralizing its target. (Resource: News Medical Net )

When IgM antibodies are present, they can indicate that a patient has an active or recent infection with SARS-CoV-2. IgG antibodies, however, develop later following infection, and generally do not begin to appear until 7 – 10 days after infection. When IgG antibodies are present, it often indicates a past infection but does not exclude recently infected patients who are still contagious, especially if detected with IgM antibodies. (Resource: CDC)

The COVID-19 antibody test is a blood test that looks for antibodies to the coronavirus. The human body produces antibodies in response to an infectious agent such as a virus. These antibodies generally arise after four days to more than a week after infection, so they are not used to diagnose current disease, but do offer insight into whether or not you have come in contact with the virus. (Resource: NPR )

If your result is positive:

• You may have antibodies from an infection with the virus that causes COVID-19.

• You may have protection from getting infected with the virus again, although this is still being researched and is currently unknown.

If your result is negative:

• You may not have ever had COVID-19.

• You may still be currently infected with COVID-19.

• As it typically takes 1–3 weeks after infection for your body to make antibodies, it is possible that you simply have not developed the antibodies yet.

• Despite being in contact with the virus, some people who are infected might not ever develop antibodies.