Antibody tests are used to detect antibodies to the COVID-19 virus to see if it’s likely that you have had the virus before.
The test works by taking a blood sample and testing for the presence of antibodies to see if you have developed an immune response to the virus.
Antibody tests differ to virus swab tests, which test to see if you currently have the virus. An antibody test cannot test if you currently have the virus.
There is no strong evidence yet to suggest that those who have had the virus develop long-lasting immunity that would prevent them from getting the virus again.
White blood cells — specifically B lymphocytes — first produce IgM antibodies after being presented with a foreign antigen, but later switch to producing IgG or IgA antibodies. IgG antibodies are the most common type to be found in the blood and have the largest part to play in conferring immunity to bacteria or viruses, while IgA antibodies tend to be found in bodily secretions such as saliva.