The difference between LFD and PCR Covid tests - as lateral flow testing becomes more widely available
Rapid lateral flow tests are now available widely in England and to those working from home in Wales
Polymerase chain reaction (PCR) tests have been widely used by the NHS during the Covid-19 pandemic.
They involve taking a swab of the inside of the nose and the back of the throat using a long cotton bud.
This allows a sample of ribonucleic acid (RNA) to be collected, which can carry the virus' generic code.
It's then sent to a laboratory for analysis which includes heating and cooling the RNA so that it multiples.
Scientists are then able to detect whether the virus is present in the sample of the person being tested.
The results of PCR tests are usually issued the following day though it can sometimes take up to 3 days.
Rapid lateral flow tests aren't sent to a laboratory for analysis, considered a "fast and simple" method.
They can detect proteins - often referred to as antigens - that are present when a person has Covid-19.
A lateral flow device (LFD) is used, similar to a pregnancy test, which can be done in the person's home.
A sample is taken from the nose and the back of the throat using a swab, similar to a PCR test, but the swab is then dipped into extraction solution and this is then dripped onto the device's absorbent pad.
This produces the reaction that gives the result, evident by the pad changing colour if Covid-19 proteins are present - with a result visible on the device 30 minutes after the sample is applied.
A line at the top of the testing strip - by 'C' - indicates a negative result. Two lines, one by 'C' and one by 'T,' refers to a positive result. A single line by 'T' indicates a void reading.
Although this form of testing is quicker than PCR testing, there have been concerns over its accuracy, with Sky News reporting that initial tests of LFDs only detected 77% of positive cases.
Full article
https://www.dailypost.co.uk/news/uk-world-news/difference-between-lfd-pcr-covid-20417030