Public Health England has approved an antibody test, made by the pharmaceutical company Roche, which may now be used to determine how much of the population has been infected by Covid-19. Antibody testing could be hugely useful as the country emerges from lockdown as the presence of antibodies to the virus in a person’s blood proves they have had it. However, whether the person is immune and if so, how long that immunity lasts, are still very open questions. The test is likely to be used to find out whether particular areas of the country, or people in certain professions, have had Covid-19, but it will not give individuals an immunity passport to let them restart their social lives. This Roche antibody test is not the home finger-prick test that created a wave of excitement when Prof Sharon Peacock from Public Health England told a committee of MPs on 25 March it would be available to buy within days. Oxford University was testing several versions of the home antibody tests, which look like pregnancy tests, at the time. All, however, failed to come up to standard. The best were said to have been 70% accurate and most no more than 50%. Health secretary Matt Hancock, who had bought 3m of them, was said to be seeking the government’s money back. Roche’s test was approved at the start of May by the EU and by the Food and Drug Administration in the USA as being 99.8% specific for Covid-19 – so it is not confused by antibodies against other coronaviruses which cause colds – and 100% sensitive, so it will pick up any antibodies that are present. It will work on blood samples taken by a healthcare professional at least 14 days after the person developed Covid-19. The Elecsys Anti-SARS-CoV-2 serology test is processed in laboratories using Roche analysers that hospitals already have. Roche says its fully automated systems can provide results in approximately 18 minutes for one single test, with a capability to do 300 tests an hour, depending on the analyser. Prof John Newton, national coordinator of the UK coronavirus testing programme, told the Telegraph that experts at PHE’s Porton Down labs had evaluated the test and confirmed the 100% accuracy. “This is a very positive development, because such a highly specific antibody test is a very reliable marker of past infection,” he said. “This in turn may indicate some immunity to future infection, although the extent to which the presence of antibodies indicates immunity remains unclear,” Newton said. Scientists will hope to obtain very valuable data on the spread of the pandemic through mass antibody testing, which could reveal how many people have had the virus but without experiencing any symptoms. Looking at those particular groups will help in the search for vaccines and treatments. Roche, based in Switzerland, already has orders from around the world, following the US approval and the granting by the EU of a CE kite mark. It had “already started shipping the new antibody test to leading laboratories globally and will ramp up production capacity to high double-digit millions per month to serve healthcare systems in countries accepting the CE mark as well as the US”, it said in a statement on 3 May. “Roche is deeply committed to supporting the global response to the Covid-19 pandemic. Timely availability and fast access to reliable, high quality tests are essential for healthcare systems,” Dr Thomas Schinecker, CEO of Roche Diagnostics, told the Guardian. “The antibody test is an important next step in the fight against Covid-19 and Roche’s antibody test can be quickly scaled and made broadly available as more than 40,000 of our instruments are already in use in many laboratories around the world.”