COVID-19 Testing Explained: PCR Vs. Rapid Antigen

COVID-19 testing has enormous value as a tool to help schools, workplaces, event organizers, and other organizations prevent the spread of the coronavirus within communities. Testing is one means of many to get people back to the workplace, the classroom, and events like concerts, conferences, and weddings. Currently, there are two primary types of tests on the market: PCR tests and rapid antigen tests.

PCR and rapid antigen tests are both diagnostic tests, meaning they’re used to determine if someone has an active COVID-19 infection. However, these two tests work in different ways to detect the virus.

Below, we break down the differences between each type of testing, their strengths and weaknesses, and best use cases.

Virus Detection

The PCR (polymerase chain reaction) test analyzes samples to detect the presence of genetic material from the SARS-CoV-2 virus. The test begins with collecting a saliva or nasal swab sample from an individual. The sample is then sent to a lab, where it undergoes a reaction to ‘amplify’ or make multiple copies of any genetic material present. This process is important as it allows the test to successfully flag even the smallest amounts of coronavirus DNA in the body. PCR tests are very accurate and can detect the virus within days of infection, even if the person is asymptomatic.

A rapid antigen test detects the SARS-CoV-2 via proteins (called antigens) that are specific to the virus. Antigens are molecules attached to viruses and bacteria that trigger an immune system response and lead to the production of protective antibodies.

Like PCR tests, rapid tests begin with collecting a saliva sample or nasal swab. The sample is applied to a test strip containing lab-made antibodies. If coronavirus antigens are present, they’ll bind to the antibodies which are part of the test strip, causing the test strip to light up as positive.

Accuracy 

PCR tests are the gold standard for COVID-19 testing because they are highly sensitive and extremely accurate.

Rapid antigen tests are less accurate and have higher rates of false-negative results than PCR tests. The accuracy of a rapid test depends on what stage the infection is in because the test requires a high amount of viral antigen in the saliva or nasal sample to detect the virus. In the early and late stages of a COVID-19 infection, a person may not have enough virus in their nose or throat for the test to flag. Rapid antigen tests are most accurate when a person is at the peak of their infection.

Testing Process and Turnaround Time

The biggest weakness of PCR testing is the time it takes to get results. While PCR tests are administered via pharmacies, clinics, hospitals, and self-administered kits, the results must be processed in a laboratory. The average turnaround time for receiving results can be anywhere from 24 hours to 2-3 days. However, if demand for PCR tests is high and labs are overburdened with tests, the turnaround time could be even longer.

The opposite is true for rapid antigen tests. They don’t require laboratory testing, and anyone can take the test at home or work and interpret the results without a medical professional’s help. On average, rapid tests take only 15 minutes to produce results. For employers, the new mandate requires any self-administered rapid antigen test to be observed by an employer or certified virtual proctor for verification purposes.

How Heed Health Can Support Your COVID-19 Testing Strategy 

The guidelines for designing an effective COVID-19 testing strategy vary from organization to organization, depending on budget, the need for rapid results, the number of people who require tests, access to tests, and other considerations.

Rapid antigen testing is a cost-effective way to conduct regular mass screenings at workplaces, schools, and events. Rapid tests are also a great way to screen symptomatic individuals.

PCR tests are not a great option for serial testing due to high costs and turnaround time. However, rapid tests are not as accurate as PCR tests and may miss early cases of COVID-19. They’re an excellent testing option to supplement rapid tests (especially for symptomatic individuals who test negative) and contact trace individuals exposed to the virus. Additionally, proof of a negative PCR test can be an effective screen to allow individuals back into a workplace or conference.

Neither test is foolproof, and neither test should be used as the only tool to prevent the spread of COVID-19. Quarantines, social distancing, masks, and vaccines should all be part of a COVID-19 prevention strategy in schools, workplaces, and events.

At Heed Health, we strive to make COVID safety simple at your organization. Our services include comprehensive COVID-19 testing programs, on-demand clinical support and guidance from medical professionals, and secure storage of testing reports and vaccination records.

Please fill out the form here to connect with our team about the testing solutions you need to operate safely.

 

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