LONDON — The group that represents hospitals in England says a shortage of COVID-19 testing is jeopardizing efforts to restore medical services and prepare for a potential surge in coronavirus cases this winter.

NHS Providers said Tuesday that inadequate testing is leading to increased absences in the National Health Service as staff members are forced to self-isolate while they and their family members wait for test results after possible exposure to the virus.

CEO Chris Hopson said that last weekend hospital leaders in Bristol, London and Leeds all raised concerns about the lack of testing.

He said hospitals “are working in the dark – they don’t know why these shortages are occurring, how long they are likely to last, how geographically widespread they are likely to be and what priority will be given to healthcare workers and their families in accessing scarce tests.’’

Home Secretary Priti Patel told the BBC it was “unacceptable” that some people were struggling to get tests, and “much more work needs to be undertaken with Public Health England.”

She says more testing slots and home testing kits were being made available as demand had risen.