The Difference Between Rapid Antigen Test and Lateral Flow

COVID testing kits are now widely available, and the type you need will depend on what you’re trying to do. In the U.K., in order for people to return to work, they must take what is called a lateral flow test. Both tests work the same way, but one delivers results faster and is required for international travel. These are available for free through government-funded health centers. They work in approximately fifteen minutes, and record the result to a “cassette,” which is then read for the results and allows you to return to work. It’s usually used to test people who are not symptomatic for coronavirus. (People who are symptomatic generally require what is known as a PCR test). Lateral tests are available through the NHS, usually free of charge.

The rapid antigen test is required for international travel. These test work by the same method as a lateral flow test, but take slightly longer to provide results. They are not available through the NHS and must be purchased through a private vendor. This test measures whether there are any antigens in your body, which will be present if you’ve had the virus.

How do they work?
The lateral flow test works similar to a pregnancy test, except that it requires a nose or throat swab. The swabs are added to a liquid, which is then applied to a strip. In less than an hour they deliver your results, read by a series of lines to determine if you’ve tested positive or negative.

Are they effective?
They are quite accurate. A study the Queen Mary University of London, the University of Oxford, the Institute for Advanced Studies based in Vienna, and the Medical University of Graz published in July 2021 found that the tests detected more than 95% of the cases found by PCR and correctly identified 89% of cases as negative. Studies on rapid antigen tests have found similar accuracy rates, with one study clocking in at 92.7%.

Where are they available?
You can get lateral flow tests for free by ordering online at GOV. The UK phoning 119 (7 am - 11 pm daily. Calls are free of charge collecting from a Covid testing centre and collecting from some pharmacies. Rapid antigen tests must be purchased through private vendors.