The appearance of Covid-19 (the first cases reported in Wuhan, China in December 2019), triggered a pandemic which necessitated the biggest global testing programme ever undertaken, with hundreds of millions of people tested so far.
Whilst human populations have endured multiple pandemics historically, this is the very first pandemic in which widespread and routine testing has been available in a global effort to contain the spread of the virus.
The testing of individuals has revolved principally around two types of test – the lateral flow test (an on-site test) and the PCR test (polymerase chain reaction test, whereby the sample is tested in a laboratory). This article explains a little more about lateral flow testing.
The Importance of Testing
First and foremost these tests have been used to detect the Covid-19 virus in humans, which is sometimes asymptomatic in infected people and is therefore transmitted stealthily. Even an infected person who develops symptoms may already have have spread the disease for 3 – 5 days prior to even experiencing the symptoms.
Sickness means absence from work or education, and has serious effects on a country’s infrastructure and economy. Testing is vital to ensure frontline staff, workforces, childcare establishments and students have reduced risk in transmitting or catching the virus to keep both individuals and the wider community protected.
The lateral flow tests are point-of-care tests, which means they can be carried out on-site, whether in a doctor’s surgery, the workplace or at home. They can be sent by mail and are easily performed and test results interpreted within minutes (30 minutes or less) without specialized training or equipment. These lateral flow tests are largely antigen-based assays. An antigen is any foreign substance that induces the immune system to produce antibodies against it.
How to do a Lateral Flow Test
- The simple test involves taking a nasal and/or throat swab (and can be done by yourself), putting the sample into the provided liquid (a scientifically formulated reagent) and then adding drops of this mixture onto the paper strip of the test cassette.
- The paper strip will react to the liquid and provide a coloured test line similar to the visual indicator provided by a pregnancy test to show a positive or negative result.
This is the type of test used in schools, universities, workplaces, prisons, care homes and private households to quickly provide an indicator of coronavirus infection status within closed environments and in individuals.
The lateral flow point of care tests can be readily – and affordably – distributed to the population without the greater cost of a laboratory test or taking too much time. It does NOT require a practitioner to take a sample from a patient, have it analysed by a technician in a laboratory, and report the results, as required by a PCR test.
If a lateral flow test proves positive, a confirmatory test, such as a PCR test, may then be carried to confirm that result.