A new COVID-19 antibody test will go live in the UK in the next fortnight.
The groundbreaking test takes a blood sample from a patient and analyses it for antibodies that will show if someone has had the virus.
If the antibodies show up as positive it will be the first clue in establishing that somebody has a degree of immunity to COVID-19.
Trials are starting to get under way at four hospitals in England including the Royal Preston Hospital in Lancashire where they are confident of being able to handle thousands of the antibody tests every day from 1 June.
Sky News was given exclusive access to the blood science laboratory at the hospital where they are preparing to start the tests.
Consultant clinical biochemist, Dr Martin Myers, explained: "If you have antibodies there then you have had that disease, that will help public health doctors decide how to unlock where we are going to go as a society, to see how many of us may have caught the disease, to see how many of us have antibodies to the disease.
"So it is really giving them the intelligence and information as to how many of us have had the disease."