A new coronavirus antibody test has been found to be 100% accurate, public health leaders have confirmed.
The examination found that Roche's serology test was "highly specific" and had an accuracy of 100%.
The test is designed to help determine if a patient has had COVID-19 and whether they have developed antibodies against it.
The detection of these antibodies could help to indicate if a person has gained immunity against the virus.
Professor John Newton, national co-ordinator of the UK Coronavirus Testing Programme, said: "This is a very positive development because such a highly specific antibody test is a very reliable marker of past infection.
"This in turn may indicate some immunity to future infection although the extent to which the presence of antibodies indicates immunity remains unclear."
A spokeswoman for the Department of Health and Social Care (DHSC) said: "Antibody testing is an important part of our strategy to counter the spread of COVID-19 and to help us understand who has had the disease.
"In addition to the recent huge expansion of the UK's swab-based coronavirus testing capacity, we are exploring the use of antibody testing across the NHS and ultimately the wider public.
"We are delighted that devices are progressing through validation, and are actively working on our plans for rolling out antibody testing and will make announcements in due course."
In March, Boris Johnson said: "The great thing about having a test to see whether you've had it enough, is suddenly a green light goes on above your head and you can go back to work safe and confident in the knowledge that you are most unlikely to get it again.
"So for an economic point of view, from a social point of view, it really could be a game-changer."
Severin Schwan, chief executive of Roche Group, said: "Thanks to the enormous efforts of our dedicated colleagues we are now able to deliver a high-quality antibody test in high quantities, so we can support healthcare systems around the world with an important tool to better manage the COVID-19 health crisis.
UK Health Secretary Matt Hancock last week said the UK was in talks with Roche about a "very large-scale roll-out" of coronavirus antibody testing.
But he acknowledged that there had been problems with antibody testing, having previously said the UK would order 17.5 million home testing kits only to find they did not work.
"There has been false hope before in antibody testing and so we'll make announcements when we're absolutely ready," he said.
Earlier this month, Roche's antibody test won emergency approval from the US Food and Drug Administration.
What is an antibody test and why is it important?
When a person gets infected with a virus, the body starts making specially designed proteins called antibodies to fight the infection.
After they recover, those antibodies float in the blood for months, maybe even years.
Therefore, an accurate antibody test can identify if someone has had COVID-19 and recovered, even if they showed no symptoms of the virus.
Current testing only identifies those who have it now.
If introduced, scientists will hope to obtain valuable data on the spread of the pandemic which will help with planning for future outbreaks as well as potential vaccines and treatments.
It will also give more accurate numbers on exactly how many people were infected to see how prevalent the virus is.
There have been suggestions those who have had the virus and have recovered will have immunity, however scientists say it is too early to be sure.
Previous tests have not been as accurate meaning they detect antibodies against other coronaviruses such as the common cold - producing what is known as a false positive.