People who test positive for Covid at home no longer need to take a PCR test to confirm the result.
Many people are still struggling to get hold of tests due to high demand.
What are the testing rules now?
If you have no symptoms:
Across the UK, if you test positive for Covid with a lateral flow test (LFT), there is no longer any need to book a PCR test to confirm that result.
You can leave self-isolation seven days after the date of your first positive test (five full days in England), as long as you have two negative LFT results, 24 hours apart.
The guidance that positive LFTs don't need a confirmatory PCR will remain in place while Covid case levels are high. Under these conditions, the vast majority of people with positive LFT results are extremely likely to have coronavirus.
People who are eligible for the £500 test and trace payment in England will be asked to take a PCR so they can access financial support.
Clinically vulnerable people in Wales and Northern Ireland are also still advised to take a PCR test after a positive LFT.
If you have symptoms:
If you have Covid symptoms - a cough, a fever or a loss of taste or smell - you should take a PCR test as soon as possible, and self-isolate while you wait for the result.
You must then continue to self-isolate if the PCR test is positive, even if you previously had negative LFT results.
However, if you have already tested positive on a LFT, you should self-isolate and do not need to take a follow up PCR.
How do I get a lateral flow or PCR test?
You can also collect LFTs from pharmacies, vaccination hubs and test centres.
You should report your LFT result online or by calling 119.
You can order a PCR test kit to be sent to your home or book an appointment at a walk-in or drive-through test site.
Are there still supply problems?
The main government website still regularly says no LFTs are available for home delivery, and many pharmacies have limited stock.
PCR test appointments are also sometimes in short supply across much of the UK, although home PCR kits are generally available.
Anyone who needs a PCR test is advised to keep checking the website, as slots are released throughout the day.
Announcing the reduction in the self-isolation period for England, Health Secretary Sajid Javid told MPs that LFT supplies had risen sharply from pre-Omicron levels, with 400 million available in January, compared to 120 million in November.
What are the rules about testing after contact with a positive case?
The testing rules are broadly similar across the UK.
If you are fully vaccinated (two doses - three in Scotland), you don't have to self-isolate, but should take daily LFTs for seven days (or for 10 days after your last contact, if this is earlier).
This also applies to people under-18s (18 and four months in Scotland; 18 and six months in England).
If any of the LFTs are positive, you must self-isolate from the date of the test, but don't need to take a confirmatory PCR test.
Close contacts of positive cases who are not fully vaccinated still have to self-isolate for the full 10 days. In Scotland, they are advised to take one PCR test and continue isolating even if the result is negative.
In Wales, unvaccinated contacts are advised to take LFTs on days two and eight, even if they have no symptoms.
Anyone who develops Covid symptoms during self-isolation should take a PCR test.
Who else needs to test?
Across the UK, NHS and education staff are asked to test twice a week. Secondary pupils should test twice a week during term time (three times a week in Wales).
There is separate testing guidance for prisons and hospital patients, as well as care home staff in Scotland.
The government has said it will provide 100,000 critical workers in England with free daily LFTs, initially for five weeks.
Critical workers deliver essential services such as transport and food distribution, and cannot work from home so are at risk of infection.
In addition, everyone is asked to test before socialising with those who are at most risk from Covid, or spending time in crowded settings or places with poor ventilation.
People can also provide a recent negative LFT or PCR result instead of proof of vaccination to enter venues that are covered by Covid passport schemes in place in England, Scotland, Wales and Northern Ireland.
You may also need to test before or after travelling abroad. You must buy private tests for this - you cannot use free NHS tests.
How do the tests work?
LFTs and PCR (polymerase chain reaction) tests do different things:
- LFTs pick up the most infectious people by detecting material from the surface proteins of the virus
- PCRs detect genetic material of the virus which can be present in the body for several weeks after somebody is actually capable of passing it on
Both tests involve swabbing your nose and/or throat. LFTs can be done at home, and show results in 20-30 minutes.
PCR test swabs must be sent to a lab for analysis, with results provided in 24-48 hours, although it can take longer to confirm a particular Covid variant.
Being vaccinated against Covid cannot cause you to test positive on either an LFT or PCR test.
How reliable are LFTs?
When LFTs were first introduced, they were criticised for being much less accurate than PCRs.
However, in October UCL researchers found LFTs were more than 80% effective at detecting any level of Covid-19 infection, which was much higher than previously thought.
LFT results are also more reliable during a period of high Covid cases, because the small number of false positives is much less significant.