20th April 2020
“Test, test, test.”
That was the message from the World Health Organisation on 16 March as the battle against coronavirus intensified. Countries all over the world have heeded the advice and the UK government is now in a race to keep its promise of testing 100,000 people per day by the end of April.
Testing for diseases is important because in most cases the quicker you can diagnose someone the better their chance of recovery. This is particularly the case for cancer where early detection and accurate diagnosis can ensure people are given the most effective treatment as quickly as possible. For coronavirus, testing serves to identify people who are infected or who have been infected with the virus in the past.
But what types of test do we have at our disposal and how do they work? Our science experts are on hand to give you the lowdown on the tests designed to remove lockdown.
The test that is already used in hospitals across the UK can tell whether a person currently has coronavirus. A swab of the nose or throat is taken and sent to a lab where a method called PCR (polymerase chain reaction) is used to check for the virus’s genetic material. PCR is also a widely used test to detect genetic material from cancer cells obtained from a biopsy. This can identify genetic markers to help diagnose a patient with cancer and help guide their treatment decision.
While a PCR test for diseases such as cancer or coronavirus can be reliable, it can occasionally lead to an incorrect diagnosis. For example, the test could wrongly diagnose someone as uninfected with the virus (called a false negative). This can happen if the swab doesn’t pick up enough of the virus or if a person is only at the beginning of their infection and not a lot of the virus is present.
The PCR test is useful because it helps health services make informed decisions about the number of intensive care beds likely to be needed or whether a healthcare worker with a cough should stay home to self-isolate.
The other test you may have heard people talking about is called an antibody test, which can tell whether a person has been infected with the virus in the past. Antibodies are molecules produced by our immune system that help us fight infections by sticking to things like bacteria and viruses. When someone is infected with coronavirus, they produce antibodies against the virus, which can be detected in a blood sample.
Unfortunately, we don’t have a reliable antibody test for coronavirus yet, but scientists all over the world are working hard on solving this problem. Several companies have developed antibody tests for coronavirus and are now in the process of testing their accuracy and reliability.
A reliable antibody test would tell us who has already been infected with coronavirus, whether they have shown symptoms or not. This test could be one way to end the current lockdown safely. It would enable us to tell who can leave their house safely and it could provide us with an exit strategy.
It’s research that underpins the technology used in the coronavirus tests. Both PCR and antibody tests owe everything to curious scientists who were simply trying to understand more about biological life. Those studying the intricacies of DNA or the secrets of our immune system would not have imagined that one day their findings would be what helps humanity end this pandemic and bring us back together.