People with acute health issues, care home residents and their carers will be first in line for a coronavirus test after a surge in demand led the government to ration tests.
Health secretary Matt Hancock confirmed that NHS staff and teachers are also priorities, while members of the public are at the back of the line.
"The testing capacity we have is valuable. And we must together prioritise it for the people who need it the most," Mr Hancock said.
Testing will also be targeted in outbreak areas and teachers will also be given priority.
Among the wider public, people in areas with high incidence will be given priority.
Speaking in the House of Commons, Mr Hancock said testing capacity was at a record high 253,521 but "alongside this record expansion, demand has gone up too".
He told MPs: "We need to prioritise the tests on those who need the most to save lives, protect the most vulnerable and make sure our health and care services and our schools can operate safely. "
Speaking in the House of Commons, Mr Hancock also announced a support scheme for people on low incomes who have been told to self-isolate.
The health secretary said the "isolation support income", starting next Monday in England, will give people on benefits £500 while they are out of work.
Equivalent cash will be provided to the devolved administrations.
Mr Hancock, acknowledging how "tough" self-isolation can be for those unable to work from home, said the fund was being announced so people don't "worry about their finances while they're doing the right thing".
He told MPs: "We will introduce a new £500 isolation support payment for people on low incomes who can't work because they have tested positive or are asked to self-isolate by NHS Test and Trace."
But he also reminded people of the new legal requirement to self-isolate, which will see rule breakers fined up to £10,000.
From Monday, police will be able to issue fines starting at £1,000 to anyone found to have ignored isolation advice, but the the most serious rule breakers could be punished with fines of up to £10,000.
He said NHS Test and Trace will "make regular checks" on people who have been told to self-isolate and will "crack down" on employers who prevent staff from following the rules.
Isolation income support will only be available to people in receipt of benefits, which in England is just under four million.
The government expects the payments to begin on October 12, but anyone told to self-isolate from September 28 will receive backdated payments once the scheme is set up in their Local Authority.
While updating MPs, Mr Hancock revealed the priority list for coronavirus tests.
First in line for a test will be those either working in acute clinical care, or those due to receive it
Second will be care home workers and residents
Third on the list are NHS staff, including GPs and pharmacists
Fourth is targeted testing for outbreak management and surveillance studies
Fifth on the list are teaching staff with symptoms
Last in line is the general public when they have symptoms and those in "in areas of high incidents" will be prioritised
Mr Hancock urged people to get a test "only if they have symptoms of coronavirus or have been specifically advised to by a health professional".
The need for "prioritisation" comes with demand for tests outstripping the system's ability to provide them, Mr Hancock said.
He added: "The testing capacity we have is valuable. And we must together prioritise it for the people who need it the most."