Severe Acute Respiratory Syndrome-Coronavirus 2 (also known as SARS-CoV-2) is a member of the coronaviridae family of viruses, belonging to the genus Betacoronavirus. Commonly called COVID-19, and informally known as simply ‘coronavirus’, it represents one of the most significant worldwide pandemics of recent decades. It is believed to have originated in Wuhan, China in December 2019, spreading across the rest of the globe in the following months. It was classified as a pandemic by the WHO in March 2020, and was responsible for shutting down most international travel and economies.
As COVID-19 continues to sweep across the globe, many countries’ priorities have turned to accurate testing and diagnosis. In this article, we’ll take a look at how to get a PCR Test for SARS-CoV-2 Coronavirus.
What is a PCR Test?
The two current tests for COVID-19 fall into two categories: RT-PCR (which stands for reverse transcription polymerase chain reaction) or serological tests. The majority of tests being conducted by governments are PCR. PCR tests are used to test for a wide range of disorders, and weren’t invented specifically to tackle the COVID-19 pandemic. They work by directly detecting the presence of an antigen, rather than the levels of the body’s immune response or the presence of antibodies.
The idea behind this is that, by testing for viral RNA before the body has had a chance to produce antibodies or even experience symptoms, the PCR test can determine whether a person is infected with COVID-19. The goal is to break the transmission chain; by testing early, trace teams have more chance of isolating everybody who has come into contact with an infected person.
Many labs (both private and public) all over the world are being utilised by governments to increase their testing capabilities. BCA-lab, in Augsburg, Germany, is one such lab. Currently, most of the demand is for sanctioned government testing, but many labs also offer individual private procedures. However, the results of these personal tests are likely to take longer to materialise because of the focus on mass state testing.
So how accurate is the PCR coronavirus test? Lab-based PCR tests have become highly dependable when it comes to COVID-19, with an 80–85% specificity rate. But it’s also important to remember that PCR tests are highly complex, and more useful for confirming the presence of an infection than providing a patient with the ‘all-clear’.
How Does the PCR Test for Coronavirus Work?
For COVID-19, the PCR test utilises a swab from the throat instead of a blood sample. This is because the majority of antigens can be found in the respiratory system of a person infected with the virus. It tests for the presence of the live virus by generating a reverse RNA transcription into DNA. The DNA is then used as a template for polymerase-based amplification (multiplication) in conjunction with fluorescent labelling and detection.
A successful amplification requires the presence of a template in the sample, and is therefore considered a positive result. The amplification is targeted to two distinct and specific regions in the SARS-CoV-2 genome, and the specificity of the amplification is achieved using primers and fluorescent probes unique to that region of the genome.
This is in contrast to serological testing, which tests blood samples for antibodies. As a longer-term test to ascertain who has previously recovered from the virus and produced the required antibodies, serological testing will be critical. But right now, governments are focused on accurate PCR testing to gauge the rate and prevalence of active infection.
How are Different Countries Tackling the Problem of Accurate COVID-19 Testing?
The procedure for getting a COVID-19 test is similar across the world. Essentially, you need to call your doctor or health authority and explain your symptoms or contact with an infected person. They will then refer you to the health officials conducting the testing, who explain when and where you can offer your sample.
Many countries are utilising PCR-based tests in the fight against COVID-19. In America, the FDA recently authorised a new variant of a PCR test that bypasses the swab-taking stage, allowing patients to spit directly into a tube. Work is being done on developing a more rapid test, but for the moment, PCR remains the gold standard.
Countries such as Germany, Ireland and the U.K. also use the PCR test as standard, but have been told they need to speed up testing if they want to get ahead of the virus. Germany in particular has a large range of 85 labs at its disposal, and a strong track record of detecting diseases early. It is suspected that the unusually low death rate in Germany, the source of much international interest, was the result of widespread early testing. South Korea, held up as a benchmark for their apparent successful navigation of the crisis, also utilised reverse transcription PCR.
The Dangers of Home-Kit Testing
With all the focus on speed and stringent social distancing, there has been developing talk of at-home testing kits. The first of these to be approved in the U.S. comes from a company called LabCorp; it is a variant of the RT-PCR test designed for home use, possibly alongside a medical professional via telemedicine.
However, these at-home kits are thought to have a drastically reduced success rate of 30–40% maximum. Although they are cheaper and easier to roll out, they will cause significant data problems down the line if they’re officially sanctioned. For now, the focus is on rapid, robust, government-sanctioned testing at designated centres, utilising the RT-PCR method.