New analysis of lateral flow tests shows specificity of at least 99.9%
New analysis shows lateral flow tests (LFD) to have a specificity of at least 99.9% when used to test in the community and could be as high as 99.97%.
Following the roll-out of millions of LFD tests in the community which has provided real world data, NHS Test and Trace has been able to conduct further analysis of rapid testing using LFDs. New findings on their specificity, which is a measure of how good the test is at detecting true negative cases, show that for every 1,000 lateral flow tests carried out, there is less than one false positive result.
The analysis of LFD tests used data from community testing, rapid testing in educational settings and asymptomatic test sites. Rapid testing in these locations uses the supervised testing model. Supervised testing is where the individual being tested swabs themselves under supervision of a trained operator, and the trained operator processes the test and reads the result.
Around one in 3 people with coronavirus do not have symptoms, which means they could be spreading the virus without knowing. Rapid testing using LFDs detects cases quickly – in under 30 minutes – meaning positive cases can isolate immediately, breaking chains of transmission.
Health Secretary Matt Hancock said: "This new data further confirms what we know – these rapid tests are extremely accurate and are helping dramatically curb COVID cases. Around one in 3 people who have coronavirus never show any symptoms but may still be infectious. This means they could be spreading the virus without realising it.
"Rapid testing can help detect asymptomatic cases quickly, preventing the virus from entering schools, colleges or workplaces, and stopping outbreaks before they occur."
Dr. Susan Hopkins, COVID-19 Strategic Response Director to Public Health England and Chief Medical Adviser to NHS Test and Trace, said: "Lateral flow devices are effective at finding people with high viral loads who are most infectious and most likely to transmit the virus to others.
"We’ve looked very carefully at the evidence that’s emerging from LFD tests that have been delivered at home and in testing sites over recent weeks, and real-life scenarios suggests they are at least 99.9% specific which means that the risk of false positives is extremely low – less than one in a thousand – which is a very good test."