COVID-19 antibody tests are rapidly becoming widely available.
These are the tests which can tell you whether or not you have previously been infected by the COVID-19 virus SARS-COV-2.
The tests look for antibodies in the blood which are made by the body in response to infection, and which reach high enough levels to be detectable from about 3 weeks after infection (or 2 weeks after symptoms began, if you had them).
Today in the UK many suppliers have sold out - people are understandably keen to know whether or not they have had the virus.
However, there have been confusing reports in the media about how we can interpret these tests and some have been temporarily withdrawn from sale over questions about their accuracy.
To what extent are these tests useful, and how can we interpret them?