About the test
Lateral flow antigen testing detects the presence of the COVID-19 viral antigen from a swab sample. The test is administered by handheld devices producing results in 20-30 minutes and is to be self-administered. Lateral flow antigen testing has a lower sensitivity than PCR. However, studies to date suggest that these tests are better at returning positive results for individuals who are infectious rather than individuals who may have had COVID-19 recently and are no longer infectious (PCR will detect both).
Innova, the LFT device being used in Lancashire, has an overall sensitivity of 76.8% for all PCR-positive individuals but detects over 95% of individuals with high viral loads, and minimal difference between the ability of the test to pick up viral antigens in symptomatic and asymptomatic individuals. This is why in Lancashire we are encouraging repeat testing every 3 to 5 days.
When used in combination with other measures such as Personal Protective Equipment (PPE), washing hands regularly and social distancing, these tests further reduce the risk of transmission. We must not relax any of these measures – this testing programme is in addition to them.
Emerging sensitivity and specificity data has been published on the Government website