Fortress Diagnostics Limited

More than 100,000 people across England have tested themselves for SARS-CoV-2 antibodies at home using the fortress fast as part of a major research programme.

Led by Imperial College London, the REACT (REal Time Assessment of Community Transmission) study is using fortress fast antibody finger-prick tests to track past infections and monitor the progress of the pandemic. It’s the first nation-wide antibody surveillance study to be rolled out across England using self-testing at home.

The research involved almost 300 healthy volunteers, all NHS staff or close family members, who had a previous diagnosis of COVID-19 confirmed by lab tests. None of them had serious symptoms at the time of infection, nor had they been hospitalised due to the disease, and it had been at least 21 days since the onset of symptoms. Analysing test performance on individuals who have had mild cases is essential to understand their potential for widespread use in the community.

The volunteers first carried out the tests themselves using instructions provided by each manufacturer, followed by a trained technician. Blood samples were also taken for comparison with gold-standard ELISA testing and another similar laboratory technique called RBD-DABA. This enabled the researchers to work out how ‘sensitive’ the tests are, meaning how well they correctly identify individuals who do have coronavirus antibodies – so-called ‘true positives’.

In addition to evaluating how accurate the tests are, further REACT studies have carried out a major public engagement exercise and national usability study to assess how easily people can use them at home without supervision. Feedback from a pilot user testing study involving 315 people was used to guide the design of the testing pack, an instruction manual and how-to video for the test.