People without Covid symptoms no longer need a PCR test to confirm a positive lateral flow in England.
The change reflects the high prevalence of coronavirus in the community and the accuracy of rapid tests, the UK Health Security Agency (UKHSA) said.
The surge in Omicron cases has seen many with positive lateral flow tests struggling to book a follow-up PCR.
The UK has capacity for more than 800,000 daily lab tests but moved closer to its limit in December.
On 23 December, a total of 622,948 PCR tests were taken and on 28 December the figure was 630,768, government figures show.
And the demand grew further in the first week of 2022, reaching 698,502 PCR tests on 6 January and 613,496 on Sunday 9 January.
It is hoped the change will improve access to PCR tests for people with symptoms and for healthcare, transport and other key workers required to test regularly.
