Millions of new coronavirus testing kits could be ready in days, rather than weeks or months, according to Public Health England.
Prime Minister Boris Johnson has previously spoken of a simple test for coronavirus as a potential "total game changer" in the battle against COVID-19.
It would show whether an individual had antibodies for COVID-19 which, if they did, would mean they could return to work if they were not showing symptoms.
Professor Sharon Peacock, director of the National Infection Service at Public Health England, revealed on Wednesday that millions of such a test have been ordered and could be used "in the near future".
However, England's chief medical officer Professor Chris Whitty was much more cautious about the tests and would not commit to a timeline for when they would become available.
"I do not think, and I want to be clear, that this is something we'll be ordering on the internet next week," he said.
Prof Whitty said the tests would first need to be evaluated, and then the main priority for testing will be identifying how many people have had COVID-19 without showing symptoms, and which NHS workers are very likely to be immune.
The test will then be "spread out" to the general population, he said.