BIOMEDICAL 16 THE SCIENTIST
OPINION Lateral flow devices
New research has used a mathematical formula to clarify how lateral flow devices are more effective than sometimes portrayed. Professor Iain Buchan, Executive Dean of Liverpool’s Institute of Population Health, explains the findings.
“P
ublic health works really well when there is a very close partnership between service and science,” says Professor Iain Buchan, Chair in Public Health and Clinical Informatics and Executive Dean at the University of Liverpool. “The most important thing is to have great science networked at national and international levels and great partnerships to embed and provoke the science at local levels. “We’ve been able to move very fast in Liverpool because of the particularly close relationship between science and [the public health] service,” he says, explaining that a long tradition of action-research for dealing with public health challenges in a deprived area prepared Liverpool to deliver world-first COVID-19 insights, such as how mass rapid-antigen testing works “on the ground”. Leading the university’s Institute of Population Health, Iain’s work focuses on data-intensive public health research for “major societal challenges”, most recently responses to COVID-19. Moving from clinical medicine to public health in 1996, Iain has a long history of “turning people’s numbers into actionable
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BUILDING CONFIDENCE IN LFDS information, really trying to close that data–action gap”. He says: “I saw a lot of underused data – I was one of the first people to describe the child obesity epidemic, using routinely collected health visitor data.” The latest research he has co-authored has found that lateral flow devices (LFDs) are more accurate than previously reported, demonstrating their reliability as a public health tool in reducing the spread of the virus. Working with researchers from University College London, Harvard University and the University of Bath, the research investigated validation studies of LFDs and showed the problem with reporting sensitivity values (the proportion of people with the infection who test positive) of LFDs relative to polymerase chain reaction (PCR) tests. The study used a new formula for
calibrating the sensitivity of LFDs, which showed they are likely more than 80% sensitive at picking up people who are infectious with the COVID-19 virus – i.e. a public health test for infectiousness and not a clinical test of for those who have been infected, but who may no longer be infectious, as is the case with PCR tests.
Different properties Previous research into the effectiveness of LFDs has compared them with PCR, suggesting the latter is the “gold standard” to show if someone is positive or negative for COVID-19. But this research highlights that LFDs work in a very different way to PCRs – they are not equivalent. LFDs detect material from the surface proteins of the virus and are very likely to give a positive result when someone is infectious. PCR tests detect the virus’
20/10/2021 18:17
