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."
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The test being used in Preston has been developed by the medical company Roche in collaboration with the NHS and involves a blood sample being taken and then analysed on existing equipment at the hospital.
The antibody testing will complement the ongoing COVID-19 testing which looks for whether someone has the virus at the time of the test.
Microbiologist Dr David Orr explained that it will still be hard to tell precisely how effective the antibodies are at killing the virus but the information that the antibodies are present could enable people to make better informed decisions.
"Especially in the healthcare system where some staff may have had it previously" he said.