As the more transmissible COVID-19 Omicron variant becomes dominant worldwide, testing capacity in many countries has reached breaking point. Many rely on rapid lateral flow tests (LFTs) to know if they have the virus or when they can leave isolation following an infection. 

Here's what you need to know about LFTs…

What are LFTs, and how do they differ from PCR tests? 

The first tests developed to identify the novel coronavirus were Polymerase chain reaction (PCR) tests. The highly accurate PCRs work by detecting a virus's genetics but take longer to give a result. LFTs were developed to fulfill the demand for a more rapid, if less accurate, identification of COVID-19. Although both are taken with a subject swabbing the nose and/or throat, LFTs work by detecting the virus's protein and can be done at home in a matter of minutes. 

Are LFTs less accurate than PCRs? 

PCRs are superior in detecting the virus as they involve a step where the genetic material is multiplied many times over, meaning even small amounts of the virus are registered. LFTs lack this process, leading to missed infection when the virus level is low – in particular during early and later stages of an infection. 

If I have symptoms, should I take an LFT? 

Due to their increased accuracy, the UK government recommends that those showing COVID-19 symptoms use a PCR test. LFTs have widely been recommended for those who work with vulnerable people and need to test regularly. Those who are testing to come out of isolation and, in part due to their ease of use, in other capacities related to safety at work and in social settings.

Can LFTs detect the Omicron variant? 

Yes. Despite rumors that LFTs do not work on Omicron, the UK Health Security Agency assured the public that "initial laboratory validation … has determined similar sensitivity to detect Omicron compared with Delta." The variance in the accuracy of LFTs is often down to their misuse. A recent study by UK-based scientists, showed that when used correctly LFTs can have an above 90 percent accuracy rate.

More information can be found on the NHS website: https://www.nhs.uk/conditions/coronavirus-covid-19/

You can find the latest advice on the pandemic from the World Health Organization here: https://www.who.int/