Everything You Need To Know About The Different Types Of Covid Tests
Since the Covid-19 pandemic started, we have all become used to the large array of testing options that are available to us, involving everything from swabbing the backs of our throats, to taking a drop of blood. It can be difficult to know which test is right for you, and how testing actually works. Here’s everything you need to know in one simple guide.
The first thing you need to know is that testing for Covid-19 works in two different ways (at its most basic level). There are tests that are diagnostic, which look for Covid-19 infection within your saliva or mucus, and antibody tests, which test whether or not your body has antibodies for Covid-19, which would suggest that you have previously had Covid-19. Diagnostic tests are the most common types of tests that we have become familiar with, as they either rule out or confirm that you have had the virus a the time of testing.
photo/ Miguel Á. Padriñán
A diagnostic Covid-19 test is performed by taking a swab at the back of the throat (across your tonsils) using a long cotton bud, and the inside of the nose. We have become used to this type of test, as it has been frequently used in schools, higher education facilities and for people to be able to travel abroad. Currently, at the time of writing (March 2021), travel abroad is illegal from the UK, and you can only travel abroad if you have an exceptional reason for doing so. The government has suspended its previous ‘travel corridor’ scheme, and now have a red-list of countries, to which travel is banned.
If you do enter the UK having visited or travelled through a red-list country, entry at the UK border will be refused and you will need to quarantine in a government-operated quarantine hotel for ten full days. Diagnostic Covid-19 testing is given to all travellers in quarantine hotels, and they must give samples on days 2 and 8 of their quarantine to check if they have the virus.
If a person enters the UK from a non-red-list country, they will need to quarantine for ten days at home or with family/friends. The government has recently introduced a scheme called ‘Test-to-Release’, which can reduce the amount of time a person spends in quarantine if they test negative after being in the UK for five days. Travellers need to book a private diagnostic PCR test from a reputable Test-to-Release provider. If they test negative, they can end quarantine. Schemes such as Test-to-Release can be rolled out by the UK government because diagnostic testing can easily rule out whether or not a person has the Covid-19 virus.
Some Covid-19 tests look for a section of the coating of the virus. These types of tests are known as antigen tests. Other tests pick up nucleic acid (such as RNA), that belongs to the coronavirus. The latter is very sensitive, and can often display that a person has tested positive, even when their body has rid itself of the virus. Antigen tests are less accurate, and can give false positive results.
The different types of Covid testing:
PCR tests
This type of Covid-19 test involves taking a swab at the back of the throat and up the nose. It is quick, and the results are highly accurate. This type of test is highly sensitive for detecting active infection. PCR stands for polymerase chain reaction, which is a lab technique that is used to detect genetic material from the virus. PCR tests can identify whether or not a person has Covid-19 within minutes, but some samples can take days to process, depending on where the sample is analysed.
Antigen tests (rapid tests)
This type of test is quick to take and use, and is often used at airports to test large numbers of people. An antigen test is taken in the same way as a PCR test, and you receive a swab at the back of your throat and up your nose, but instead of waiting multiple days for results, an antigen test can produce a result in less than an hour. Antigen tests are also very accurate, but are more likely to miss an active infection in a person’s body. Some people may take this type of text with Covid-19 symptoms, but subsequently test negative. At this point, a PCR test may be needed.
Antibody tests
An antibody test checks whether there are any antibodies for Covid-19 present in a person’s immune system – it doesn’t detect whether or not they actively have the virus in their body. Antibody tests can tell if a person has been infected with Covid-19 in the past for up to several months. It is not possible to test for antibodies until several days after infection. A healthcare professional needs to administer this type of test, as it requires taking blood from an arm vein or a prick from a finger.
Travelling and working abroad does involve a lot of Covid testing! Get familiar with the most suitable test for you to make your travels during the pandemic as safe as they possibly can be.
Author: Chad Harwood
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