A lack of coronavirus tests for NHS staff is leading to staff absences and services being put at risk, hospital bosses have warned.
NHS Providers, which represents English hospital trusts, said staff are having to self-isolate because they cannot get tests for themselves or family members.
It comes after widespread reports of people struggling to get tested.
The home secretary said the government was "surging capacity" where it was needed.
The government's testing system - part of its test, track and trace operation which Prime Minister Boris Johnson promised would be "world-beating" - has faced criticism in recent weeks.
An increase in demand for coronavirus tests has led to local shortages, with some people being directed to test sites hundreds of miles from their homes.
Meanwhile, there have been fewer than 100 Covid-19 deaths in a week in the UK for the first time since March, according to Office for National Statistics figures.