What is a lateral flow test?
Lateral flow antigen tests are a new kind of technology that can be used to test a higher proportion of asymptomatic people (people without COVID-19 symptoms), better enabling us to identify and isolate those who are at high likelihood of spreading the virus.
How the tests work
A lateral flow test detects the presence or absence of coronavirus from a swab or saliva sample. The sample is mixed with a buffer solution, which releases and breaks up virus fragments.
Some of the solution is then dropped on to the lateral flow device. The sample runs along the surface of the devices’ absorbent strip, showing at the end a visual positive or negative result dependent on the presence of the virus.
Lateral flow tests are validated technology that is safe, inexpensive and the results are trusted.
Extensive clinical evaluation from Public Health England and the University of Oxford show they are specific and sensitive enough to be deployed for mass testing, including for asymptomatic people.
Find out more on GOV.UK about how lateral flow tests work.
Who the tests are for
The tests are available for anyone who has to leave home to attend work, such as taxi and bus drivers or retail workers.
They are also for people who are in contact with vulnerable individuals, such as paid and unpaid carers, and volunteers.
We aim to use these tests to identify people who do not have COVID-19 symptoms but who are infectious and could spread the infection to others unknowingly.
It is not mandatory to take a test but we are hoping that many people will recognise the benefits of getting involved in local testing efforts to reduce the spread of the virus in their communities.
Are these tests less accurate than PCR tests?
Lateral flow and PCR tests have different characteristics and different uses.
PCR tests have higher specificity and sensitivity but require a laboratory to process results and are therefore slower and more expensive. They are therefore well suited to specific use cases, such as those with COVID-19 symptoms.
While lateral flow tests have lower sensitivity than PCR, they deliver results far faster and do not require a lab, making them more scalable.
As such, they allow us to test far larger numbers of asymptomatic people and get them their test result faster than with PCR technology.
This will enable us to identify a large percentage of people who are infected and infectious, but asymptomatic and unaware of the fact that they are possibly spreading COVID-19.
Taking a test
Taking a lateral flow test usually involves taking a sample from the back of the throat near the tonsils and from the nose, using a swab.
It takes less than 15 minutes to administer the test and because lateral flow devices do not need to be sent to a lab, results are available within an hour.
The swabbing and processing of tests is conducted at the dedicated testing site by trained personnel.
If you get a positive result, it is likely that you were infectious at the time the test was taken.
The test cannot detect very low levels of coronavirus in a sample, so if you have only recently been infected, are in the incubation period, or if you have mostly recovered, the test may not give a positive result.
If you test positive
If you test positive with the rapid lateral flow test you will need to self-isolate for 10 days.
Eligible individuals who test positive will be entitled to the £500 Test and Trace Support Payment in the same way as a regular swab test through NHS Test and Trace. Please note the government has laid down eligibility criteria.
If you test negative
You must continue to follow the preventative measures currently recommended for stopping the spread of the virus. To protect yourself and others, you must remember: Hands. Face. Space.
- Hands – wash your hands for 20 seconds with soap and water often, and as soon as you get home – use hand sanitiser gel if soap and water are not available.
- Face – wear a face covering in indoor settings where social distancing may be difficult, and where you will come into
contact with people you do not normally meet.
- Space – stay at least 2 metres away from anyone you do not live with, or who is not in your support bubble.
If you have COVID-19 symptoms
Free testing for COVID-19 continues to be available to everyone in Devon. If you have symptoms (high temperature, continuous cough or loss of/change in taste or smell) you can book a test online or do so by calling 119.