Most people displaying symptoms of coronavirus in the UK can refer themselves for a test - but can employers refer you, too?
Here's what you need to know.
Who is entitled to a test?
Currently, anyone in England and Wales with symptoms of coronavirus can ask for a free test through the NHS website, regardless of their age.
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In Scotland and Northern Ireland, anyone aged five or over with coronavirus symptoms can refer themselves for a free test.
One test is given per person, and you can choose between having a home test delivered, or booking an appointment at a test site.
Can employers test workers?
Your employer can refer you for a test if you are an essential worker who is self-isolating either because you or member(s) of your household have coronavirus symptoms. This route is available to employers in Scotland, Northern Ireland and England.
However, some employers may be testing workers regularly, even in the absence of symptoms.
This is the case with many healthcare workers and hospitality staff, who have regular face-to-face contact with others.
Do I have to pay to be tested?
If regular testing is required, the cost will usually be covered by your employer.
However, while the upfront cost of regular testing may be covered by your employer, tax authorities have confirmed that workers will have to pay tax on tests.
The tests will be treated as benefits in kind - benefits employees receive from employers that are not included in their salary. Sometimes these are referred to as "perks" and usually relate to things like private medical insurance or company cars. Other benefits can be tax free, such as canteen meals.
The HMRC guidance, published on Monday, stated, "Coronavirus (Covid-19) testing kits or tests carried out by a third party which have been purchased by you to provide to your employees are treated as a taxable benefit in kind on the employee."
There has been some backlash to the idea, with Treasury Committee chairman Mel Stride warning that the move may cause employees to avoid employer-sponsored tests.
Chancellor Rishi Sunak has said he will look into the issue "very quickly".