COVID-19 Screening & Testing: Knowing the Distinctions

September 14, 2020

Categories: COVID-19, Health, Safety,

More than nine out of 10 travelers grounded due to the pandemic declared their willingness to subject themselves to screening and testing if it meant a return to leisure and business trips domestically and internationally. That’s according to a Global Rescue survey conducted in the spring when COVID-19 testing methods were in their infancy and screening was increasing in complexity as new symptoms were identified.

No one knows, yet, how long the pandemic will last or when definitive treatments and vaccines will be available. What we do know is that traveling outside your home, your state or your country is a viral risk exposure that’s largely mitigated through well-known behaviors – like physical distancing, hand sanitizing and mask-wearing.

Beyond those personal conduct measures there are checks available and even required, that are important for minimizing or even eliminating the risk of COVID-19 infection.

“Unfortunately, there is tremendous public confusion about the needs, effectiveness and purposes among the various tests and screenings: viral tests, nasal or oral swabbing versus saliva tests and anti-body testing,” said Medical Director Dr. Claudia Zegans.

They are not all the same, but each contributes to the effort to control the spread of the virus.

Screening vs. Testing

Screenings are not tests, but a screening could lead to a test. Testing can be a part of a screening process and with some organizations or medical facilities, it may be the primary mode of screening.

A COVID-19 screening can be as discreet as completing an online questionnaire – like this one by the Mayo Clinic – or a hybrid of online and in-person screening – like this one for hair salons and barbershops in California or this one for travelers to Hawaii.

Screenings typically include a series of questions for individuals about their current health, exposure to an infected person and COVID-19 symptoms including: fever, cough or sore throat, shortness of breath or trouble breathing, chills or repeated shaking with chills, muscle aches, nausea, vomiting or diarrhea, loss of smell or taste, or headache.

Temperature checks for fever are increasingly common, especially in schools, businesses and airports. Yet Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said the White House and the National Institutes of Health abandoned temperature checks as they’re “notoriously inaccurate.”

Antigen vs. Antibody

If someone displays COVID-19 symptoms, screening programs will either urge the individual to obtain a COVID-19 test or conduct one on the spot. But screening for symptoms is not fool proof.

According to NBC News, the majority of people who tested positive for the virus were asymptomatic. Screenings are an important line of defense against viral spread, but there are huge gaps in their effectiveness.

Testing closes many of the gaps screening leaves open. There are two different types of tests – diagnostic tests and antibody tests.

“An antibody test uncovers whether you had a COVID-19 infection. It can take as long as several weeks for antibodies related to a viral infection to develop and – once they do surface – they can remain in your system for several more weeks or longer,” Zegans said.

The Food and Drug Administration (FDA) reported researchers don’t know if the existence of antibodies means you are immune to the coronavirus in the future. The main takeaway, however, is that antibody tests are not the tool to use to diagnose whether someone has a coronavirus infection.

A diagnostic test can show if you have an active coronavirus infection, regardless of your symptoms.

Currently there are two types of diagnostic tests which detect the virus. One kind are the molecular tests, like RT-PCR tests, that detect the virus’s genetic material. Results are sometimes available within a day or two, but time frames up to a week or more are not unusual.

The other type are antigen tests which detect specific proteins on the surface of the virus. The antigen test can be done at the point-of-care with results typically available in less than an hour of the test.

“Diagnostic testing may sound simple, but it’s not. The cost of different tests varies widely. A recently announced antigen test claims to cost about $5 per test. Other tests are ranging between about $10 to as much as $119 per test or more, but test makers are finding ways to bring the cost down and for good reason. Widespread testing needs to be affordable to make certain the expense is not a barrier to testing and ultimately controlling the outbreak,” Zegans said.

The method of specimen collection is important, too, as is the speed of delivering results. For example, deep nasopharyngeal swabbing is less comfortable than anterior nasal or oropharyngeal swabbing.

Collecting saliva for testing from someone who spits into a sterile container can be done with minimal discomfort – a welcome alternative to the uncomfortable four-inch nasopharyngeal swab inserted into your nostril or throat.

There are breathalyzer tests currently under development that simply require individuals to blow into a tube or similar sample collection container.

Some molecular tests can deliver results at the point of care in less than one hour. PCR tests – a specific type of molecular test commonly used to detect COVID-19 infection – done at labs, hospitals and research facilities can deliver results in one to two days but long delays have been noted.

Antigen tests results can be ready within an hour. One pharmaceutical company announced recently an antigen test delivering results in 15 minutes.

Accuracy, False Positives and False Negatives

“There are more tests in various stages of development and availability – each with different levels of accuracy, such as the likelihood of false positive results or the percentage of false negative results,” Zegans said.

Some tests are less accurate than others, delivering a percentage of false positives or false negatives ultimately requiring more testing. Interpretation of the accuracy of test results is also complicated by how much disease is circulating in the community (i.e., the likelihood of having the infection) and whether you have symptoms or not.

For example, molecular diagnostic tests – the ones that typically require nasal or oral swabbing although there are a few molecular tests using saliva specimens – are generally highly accurate and usually do not need to be repeated.

Comparatively, antigen tests, requiring nasal or oral swabbing but delivering results in 15 minutes, usually have adequate results for positive indications of infection but unfortunately, also tend to deliver false negative results, often requiring confirmation using a molecular test.

Developing tests, let alone vaccines, for a new and dangerous virus requires resources, time and cooperation among the researchers, the manufacturers, the government and the public.

To help move the process along more quickly and as safely as possible, the FDA issues Emergency Use Authorization, or EUA, “to provide more timely access to critical medical products that may help during the emergency when there are no adequate, approved, and available options.”

The EUA process is not the same as full FDA approval, rather it’s a speedier FDA evaluation of the options and evidence available. The FDA has issued hundreds of EUAs for diagnostic tests and antibody tests.

The Travel New Normal

As travel re-opens caution and concern will be top-of-mind among travelers. Global Rescue provides a broad set of services designed to minimize the risk of COVID-19 exposure and in the event of an infection, provide mitigation and remediation assistance by implementing guidelines from the leading health and medical authorities.

“Screening, testing and triage for all travelers before, during and after their journey is the gold-standard protocol for the safety of tourists and the people they’re visiting,” said Global Rescue CEO Dan Richards.

Global Rescue offers a complete COVID-19 solution that includes end-to-end COVID-19 planning, testing, monitoring, response and emergency action plans for governments, organizations and businesses to implement.

The program includes triage and testing for symptomatic travelers, housing resources to accommodate traveler quarantines, coordination of hospital admission, ground and air medical evacuations for COVID-19 positive travelers, and monitoring and data collection for all COVID-19 positive travelers from diagnosis through repatriation. Click here for more information.

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