If you are considering implementing an on-site COVID-19 testing program (workplace, community or elsewhere) or if you have already started, you’ve likely realized you have quite a few questions to answer and decisions to make. An important component of a successful workplace testing program involves having a robust testing strategy. This will determine the workload on your team, and most importantly, impact on your productivity and will provide you with a plan for when and who to test.
Let’s look into some of the important questions your testing strategy should address.
Why are we testing?
Testing provides you with the power of knowledge. Knowing if employees are potentially infectious or not will help with making important decisions about how you conduct your business. With on-site COVID-19, an organization can:
- Create virus-free work zones, allowing your staff to work safely and with confidence.
- Make timely and informed decisions to implement the organization’s response to COVID-19.
- Provide peace of mind to employees, customers, and community members.
- Make it easy for staff to test frequently, and avoid visits to centralized testing facilities, and long test turnaround times.
- Contribute to the overall testing effort in their community and help stop to spread of COVID-19.
When creating your strategy, it’s important to keep the reason you are building a testing strategy front of mind. It will help you focus on what you hope to achieve and provide a framework for the decision you’ll need to make while building and implementing your strategy.
What kind of test should we implement?
For any approved COVID-19 test currently on the market, be it antigen or PCR based, there should not be any reliability concerns, if these tests are conducted properly, by the appropriate personnel, and using the appropriate space, equipment, and reagents to conduct the test. The real question should be about which type of testing to use for specific information regarding the COVID-19 situation.
PCR tests are currently the most commonly used type of test to detect whether a person has an active COVID-19 infection. These tests look for genetic material from the SARS-CoV-2 virus that causes COVID-19. Once a sample is collected by a health care professional, these tests can be done quickly (1-2 hours) at the place of testing or can be done in a large central lab (anywhere from a few hours to a few days). These tests are the gold standard and can be used to diagnose a COVID-19 infection without any additional confirmatory tests. They often require specialized equipment to run the test (ex. a thermocycler) but with the right set up can be used in a remote setting. Mobile RT-PCR solutions, such as our Biomeme SARS-CoV-2 test, are portable, rapid, cloud-connected, provide accurate results and use a very small footprint in a dedicated room. With this new generation of portable thermocyclers, there’s no need for an expensive laboratory setup. A trained clinical laboratory personnel can, with proper training on the equipment (usually 1 or 2 days), run tests and deliver results in a very short period of time, generally around 2 hours.
Antigen tests, often referred to as “rapid tests” are also used to detect if a person is currently infected, but tend to perform better if a person has had symptoms for a few days. These tests are designed to detect pieces of the proteins that make up the virus. Once a sample is collected by a health care provider, antigen tests can often be done quickly (a few minutes to about an hour or so), but occasionally they are sent to a central lab. One thing to keep in mind is that for the current antigen tests on the market, an additional PCR test might be required to confirm an antigen test result. These requirements vary by location so make sure you check with your local health authority.
For further information about test differences please take a read through our “Antigen, Antibody or PCR tests: What is the difference?” blog.
What aspects of the test are important?
Even though you may have figured out if you want to test with PCR or antigen, it’s important to remember that not all tests are created equal. The main driving factors for consideration should include:
- Accuracy: It’s important to have a test that is both highly sensitive and specific, as this enables detection of the virus. Sensitivity is the ability of a test to correctly identify those with the disease (true positive), whereas specificity is the ability of the test to identify those without the disease (true negative). This is crucial as the disease continues to spread if a positive patient is reported negative (a false negative – more on this later). There are three main factors that boil down to the accuracy of the test.
- Sensitivity of the test itself and how accurate it is.
- Sample collection and preparation (ensuring it does not get contaminated)
- Sample collection timing. This pertains to the amount of viral load that can be collected and detected as per either PCR or antigen, which have different levels of detection at various points of infection. That the beginning of the infection the viral load is smaller, therefore harder to detect. A higher accuracy test will be able to detect a lower level of the virus, earlier on in the infection cycle, playing an important role in early detection.
- For example, our mobile COVID-19 PCR test performance is in concordance with reference testing in clinical analysis and validation studies.
- Speed: Ensure the time it takes to get results from your chosen test matches with your testing strategy. Oftentimes, an onsite testing program is initiated to protect an onsite workforce. This kind of strategy typically requires fast results, so a quick decision can be made should an employee or visitor test positive. Our Biomeme COVID-19 test delivers 9 test results in about 60 minutes (excluding RNA extraction).
- Convenience: Most employers setting up onsite testing don’t have the luxury of a large laboratory, or extra space to house bulky lab equipment. This means its important to find a testing system that is convenient, simple and fits well within parameters of your facility. Our test is portable, comes in a carry-on sized hard case, weighs less than 3lbs and can run on a battery for up to 5 hours, enabling SARS-CoV-2 testing in even remote locations. Mobile tests can be performed on-site, in healthcare settings, clinics, schools, workplaces and more importantly remote and pop-up community testing sites.
- Simple: If a test is overly complicated it will extend the test result process and will require additional personnel and training on how to operate the test. Our PCR mobile solution can be broken down into 3 easy steps: Collect the sample (swab), prepare the sample (RNA extraction) with a very simple and easy extraction process that uses lyophilized reagents – this avoids mixing, and combining wet chemistry. And lastly, process the sample by placing it in the thermocycler and letting it run its course.
- Digital Results: Look for a test that includes the added security and convenience of digital and anonymous results. Your test results will be provided through a smartphone with our mobile solution.
- Unaffected by variants: As variants are emerging it’s becoming more and more important to test for COVID and to ensure that your test isn’t affected by these variants. Look for test options that are unaffected by these variants to ensure you have expanded capabilities of these tests. Our Biomeme’s SARS-CoV-2 assay is unaffected by the most recent B.1.1.7 (UK), B.1.351 (South Africa), P.1 (Brazil) B.1.427 and B.1.429 (California) variants.
A quick note on the potential false negative topic as it relates to the Accuracy section above. False negatives are more elusive than false positives. They can be attributed to wrong sample preparation or a defective reagent. But what about the sensitivity of the test?
Patients with symptoms rarely returned with false negative results. But patients not showing symptoms, where the sample was taken 5 days or more before symptoms onsets, are highly susceptible to return a false negative because the viral load may be too low for detection. This means that in principle people without symptoms testing negative should ideally be retested 5-6 days later.
A study published in Annals of Internal Medicine, in August 2020, reviewed 7 previously published studies, testing 1330 people, to establish an estimate of the false-negative rate by day since infection. Samples collected from the upper respiratory tract have different rates of testing positive depending on how far into an infection a person is, according to this study
The chart below illustrates that over the 4 days of infection before the typical time of symptom onset (day 5), the probability of a false-negative result in an infected person decreases from 100% (95% CI, 100% to 100%) on day 1 to 67% (CI, 27% to 94%) on day 4. On the day of symptom onset, the median false-negative rate was 38% (CI, 18% to 65%). This decreased to 20% (CI, 12% to 30%) on day 8 (3 days after symptom onset). This is important as it shows the importance of sensitivity in a test, and also illustrates that the timing of sample collection can affect the results greatly.
Who should be tested? And How Often?
A screening protocol needs to be created and this includes deciding on who will be tested. Here are some guidelines that can help with establishing a protocol.
- CDC recommends that anyone with any signs or symptoms of COVID-19 get tested, regardless of vaccination status or prior infection.
- WHO recommends anyone with symptoms should be tested, wherever possible. Those who do not have symptoms but have been in close contact with someone who is, or may be, infected may also consider testing – contact local health guidelines and follow their guidelines.
- Health Canada recommends health care professionals assess people based on their symptoms, underlying medical conditions, and risk of exposure to the virus. Health Canada also states that Public health authorities in every region have developed their own approach for testing people based on the local context. Contacting your local public health authority for more information is the best way to figure out how who and how frequently they should be tested.
Setting a protocol for who and when they get tested can include the following:
- Testing contractors/visitors (voluntary) as they show up on-site.
- Testing employees – this cadence should be best suited for how frequently the employees comes and goes from the site. If it’s shift work, you can test every few days, if they are on-site for a few weeks, an initial test, and then perhaps a few days to a week later to ensure a false negative was not captured.
According to the CDC guidelines if a test is negative, this means that SARS-CoV-2 was not found in the specimen. However, a test could show a false negative if the specimen was collected too early in the infection. In this case, the same person who initially tested negative could test positive later during their illness. While during those days they would have been exposing others as well as a false negative test enabled them to carry on with others.
- Some departments or employees may need to be tested more frequently than others, and that will depend on how often they interact with others, and if they are at a higher risk of exposure. Ex. The supply chain/delivery department will have more frequent exposure to others and be at a higher risk of infection, versus the internal office employee.
- An employee/contractor/visitor with symptoms should be tested.
- An employee/contractor/visitor who has travelled should be tested.
- Implementing a screening process/questionnaire, consent forms, and other measures to keep everyone safe (masks, sanitizers, distancing etc.) should also be implemented regardless of what testing methods you do or do not implement.
What will you do if you have a positive result?
In the case that there is a positive test, the Public Health Agency of Canada (PHAC), in collaboration with Canadian public health experts, has developed guidance for federal/provincial/territorial (FPT) public health authorities (PHAs) to support the management of individuals infected with or who may have been infected with COVID-19 (i.e., “cases”) and contacts of COVID-19 cases within their jurisdictions.
It is important for health care providers to notify PHAs of cases of COVID-19 in accordance with jurisdictional reporting requirements. PHAs need to provide overall co-ordination with health care providers for the management and reporting of cases, and to establish communication links with all involved health care providers for the full duration of illness. PHAs should report confirmed cases of COVID-19, as well as probable cases where feasible, to PHAC within 24 hours of receipt of their own notification. Further information is available through the National surveillance for Coronavirus disease (COVID-19) guidance.
Why do you need to keep testing even with the vaccine?
Slow rollout of vaccines, based on current supply Health Canada estimates that the majority of Canadians will be fully vaccinated by September 2021, until then and months after, keep masking, social distancing, and diagnostic testing.
It is still unclear how long COVID-19 vaccines can protect people (CDC, Fully Vaccinated), and testing will be able to diagnose an infection and help control the spread.
The currently approved vaccines are found to be effective in preventing a person from being infected with COVID-19. One dose of either the Moderna or Pfizer vaccine was found to be 80% effective in preventing a person who received the vaccine from being infected with COVID-19, while two doses appeared to be 90% effective at preventing the person from becoming infected. While spreading the virus from a vaccinated person to unvaccinated people is low, it’s possible. This is why fully vaccinated people should still be precautious and continue safety measures.
It’s important to understand that a viral (antigen or PCR) test detects if there is a current infection, and a person will not test positive after getting a COVID-19 vaccine. However, after getting vaccinated and developing an immune response, some antibody tests might test positive. It is important to note however that antibody tests are not used to screen for current infection, they only indicate a past infection. (CDC, Fully Vaccinated)
In summary testing for COVID-19 helps protect our employees, coworkers, elders and the community at large. As per Health Canada, testing still remains the only way to confirm if someone currently has COVID-19, and it is an important tool to:
- Stop the spread of the virus and preventing community outbreaks
- Detect and isolate people who have COVID-19
- Follow up with close contacts of someone confirmed to have COVID-19 (contact tracing)
- Better understand the virus
Getting tested provides positive or negative diagnosis of COVID-19, which helps to minimize the spread by ensuring positive cases follow proper protocols and isolate from others. It can also assist with contact tracing, which is done confidentially by public health officials or other appropriately trained people. Testing is, and will continue, to play an important role in getting back to a more ‘normal’ pace of life and restarting our economy.
 Variation in False-Negative Rate of Reverse Transcriptase Polymerase Chain Reaction–Based SARS-CoV-2 Tests by Time Since Exposure, Lauren M. Kucirka, MD, PhD, Stephen A. Lauer, PhD, Oliver Laeyendecker, PhD, MBA, Denali Boon, PhD, Annals of Internal medicine, August 2020
 Thompson MG, Burgess JL, Naleway AL, et al. Interim Estimates of Vaccine Effectiveness of BNT162b2 and mRNA-1273 COVID-19 Vaccines in Preventing SARS-CoV-2 Infection Among Health Care Personnel, First Responders, and Other Essential and Frontline Workers — Eight U.S. Locations, December 2020–March 2021. MMWR Morb Mortal Wkly Rep 2021;70:495–500. DOI: http://dx.doi.org/10.15585/mmwr.mm7013e3external icon.