Lateral flow tests (LFTs) have been shown to be 95% effective at detecting Covid-19 if used at the onset of infection and soon after symptoms start, according to a new study.
The tests are cheaper than PCR assessments sent to laboratories and return results in 30 minutes rather than taking up to three days.
Researchers said earlier studies suggested LFTs may be less sensitive than PCR in detecting Covid-19.
More than 2,500 people with mild to moderate flu-like symptoms were assessed by general practitioners in Liezen, Austria, between 22 October and 30 November for the study by the Queen Mary University of London, the University of Oxford, the Institute for Advanced Studies based in Vienna, and the Medical University of Graz.
They were tested for viral antigen using LFT and those suspected to have Covid-19 were also examined with a PCR assessment.
The LFT detected more than 95% of the cases found by PCR and correctly identified 89% of cases as negative.
The study is the first to compare the two modes of testing on the same group of people on a large scale and included variables such as different brands of test kit, three laboratories being used and professional swabbing undertaken at 20 separate general practices.
Study author Dr Werner Leber from Queen Mary University of London said: "Previous studies have suggested lateral flow tests may be less sensitive than PCR in detecting Covid-19, particularly among asymptomatic individuals and during the early or late stage of an infection when the viral load is lowest.
"But we have found that in patients who are newly symptomatic, the two testing methods have similar levels of accuracy.
"Countries are considering using lateral flow tests to manage future waves of the pandemic. Our findings support this move, but ensuring tests are properly administered should be integral to any strategy."
Dr Jasmina Panovska-Griffiths from the Big Data Institute and The Queen's College at University of Oxford added: "In our study, both shorter duration of symptoms and higher viral load were significantly associated with positive lateral flow tests.
"This highlights the necessity of testing at early infection with lateral flow tests, and shows that in patients who are newly symptomatic, the two testing methods have similar levels of accuracy.
"Our study is the first study to demonstrate that point-of-care antigen testing using lateral flow tests combined with clinical assessment of symptomatic patients can rapidly and accurately detect Sars-CoV-2 infection in primary care."
It comes after scientists involved in the mass testing pilot in Liverpool said on 7 July that the speed at which test results are available using LFT compared to PCR tests saved around a day in the time it takes to identify someone as likely to pass on the virus.
