Q: What is the new test?
A: Pharmaceutical giant Roche has developed a test which can tell whether somebody has had coronavirus. It involves taking a small sample of blood and testing it for antibodies which indicate exposure to coronavirus. Public Health England has evaluated the test and approved it as being safe and reliable for widespread use.
Q: How reliable is it?
A: Very. The test picks up 100% of people who have had coronavirus. This means it has 100% sensitivity. It also has a specificity of over 99.8%, meaning it picks up virtually all people who have not had coronavirus. A test that is 100% specific means all healthy individuals are correctly identified as healthy - there are no false positives.
Q: What if I've never had any symptoms of Covid-19?
A: It doesn't matter. Experts believe a proportion of people who get Covid-19 do not develop symptoms. The test can identify people who have had coronavirus, even if they never had any symptoms.
Q: If the test shows I've had Covid-19, am I now immune from it?
A: Scientists are unsure and there is still a lot to learn about coronavirus. Experts believe that while the presence of antibodies indicates a level of immunity, it is unclear whether people are completely protected and how long any immunity lasts. There have been some suggestions that immunity could last for two to three years, but more work still needs to be done.
Q: Can I get the new test?
A: Not yet. The Government plans to first roll out the new test to frontline workers, such as people employed in health and social care. It is hoped that the test will eventually become available to the wider public, although it is unclear whether this will be via the NHS or through commercial websites. Roche says it will be able to provide hundreds of thousands of tests to the UK every single week. If it proved people were definitely immune, they could safely go back to work and could socialise with other people without the fear of catching or spreading the virus.
Q: How does the test work?
A: A blood sample is processed by centrifuging or spinning it using automated equipment already installed at NHS sites across the UK. This makes a part of the blood called the serum, which contains antibodies for all sorts of problems, rise to the top. Chemicals called reagents are then added to it and, if Covid-19 antibodies are present, the chemicals trigger a light reaction which a machine then detects.