As mass coronavirus testing continues across Liverpool, here the PA news agency looks at the various types of test available.

Covid-19 tests are split into two different categories, with one aiming to find out if a person is infected, while the other determines if they have had it in the past and have produced antibodies.

– Polymerase chain reaction (PCR)  tests

These are currently the most widely used tests, but can only determine if a person is infected with Covid-19 at the time.

It does not show whether they have had it and have since recovered.

The tests work by first taking a swab from the person’s nasal passage or from the back of their throat.

It is then tested to see if the virus’s genetic material, called RNA, is present.

They usually take between 12 to 24 hours to return results.

– Antigen testing

Unlike PCR tests, which detect the virus’s genetic material, antigen testing looks for proteins that are specific to the virus.

They require a swab to be taken and are also only used to determine whether a person is currently infected.

The process is usually quicker than PRC testing and can provide results in as little as 15 minutes.

– Loop-mediated isothermal amplification (LAMP) testing

Similar to PCR tests, LAMP testing also works by detecting whether the virus’s RNA is present in a sample.

However, the technology is able to produce results much quicker – in as little as two to three hours.

While the tests also involve collecting nose and throat swabs, samples from mucus produced through coughing can also be used.

Lamp technology was due to be used to test NHS staff in Liverpool as part of the mass testing pilot scheme for the city.

– Lateral flow tests

These portable tests can process samples on-site without the need for laboratory equipment, with most generating results in under half an hour.

They are also able to detect coronavirus in people who do not show symptoms and are being used in the Liverpool testing pilot.

While the swabbing and processing needs to be conducted by trained personnel, health officials are now looking at how the test could be self-administered.

– Antibody testingThese tests are used to tell if a person has previously been infected with coronavirus.

Using a blood sample, the tests determine whether antibodies – which are produced by the immune system to fight the virus – are present.

Pin-prick antibody tests which allow people to submit their own sample are not yet widely available in the UK.