A new form of Covid-19 test which can produce results in just 15-30 minutes is set to be rolled out across the globe, the World Health Organisation (WHO) has announced.

The World Health Organisation last week approved the tests for emergency use.

But how does the new test work and why is it important?

How the test works

The antigen-based rapid diagnostic tests work by detecting proteins found on the surface of the virus.

The tests look similar to pregnancy tests, showing two blue lines for a positive result. 

Crucially, results can be yielded within 30 minutes of taking the test.  

How is it different from other tests?

Most of us who have already been tested for coronavirus will have experienced a nasal/throat swab. 

Nasal/throat swabs and finger-prick blood tests require laboratory processing to produce results, which can take days, whereas the rapid-antigen tests do not. 

This means they are able to detect the virus within minutes, compared to the hours or days necessary for the genetic tests - or PCR tests.

They are also far cheaper - with each test costing around £3.90 each, compared to £100-200 pounds on average if the genetic tests are issued privately.

However, they are generally considered less accurate than laboratory-based tests.

How important are these new tests in the fight against coronavirus?

The rapid antigen tests will be vital in improving the testing capacity of lower and middle-income countries who lack enough laboratory resources or trained health workers to properly carry out PCR tests.

They will also allow health care workers to get a better grip on where the virus is circulating in poorer countries, in hopes of following up with containment and other measures to stop it.

Peter Sands, executive director of the Global Fund, a partnership that works to end epidemics, said the tests represent a “significant step” in the effort to combat and contain the virus on a global scale.

He said: “They’re not a silver bullet, but hugely valuable as a complement to PCR tests.”

When will the tests be available?

The World Health Organisation and its leading partners have agreed to deploy 120 million rapid-diagnostic tests as early as next month.

Catharina Boehme, chief executive of a non-profit group called the Foundation for Innovative New Diagnostics, said the initial rollout would take place across 20 countries in Africa.

What do the new tests mean for Scotland?

The rapid-antigen tests will primarily benefit poorer countries, although wealthier countries that sign up to the Access to Covid tools initiative - like the UK - will also be given access to them.

If made available, they could facilitate mass testing, however it is unknown whether the UK or Scottish Government intends to purchase them.

Meanwhile, a number of walk-in coronavirus testing centres have opened across the country, including the Usher Hall in Edinburgh and the ARC sports centre in Glasgow.