Coronavirus testing is commonly an unpleasant experience in which a health care provider pushes a torturously long swab up your nostril.
Since late March, three Southern California jurisdictions _ Los Angeles County, and the cities of L.A. and Long Beach _ have offered a more palatable alternative to this nasopharyngeal sampling, whose very name poses a challenge. At 21 drive-thru sites, anyone can now provide a sample by swishing a cotton swab around their mouths, putting it in a tube and dropping it in a receptacle on their way out – all within the comfort of their cars.
Some experts suggest this self-sampling approach may provide an easier way to ramp up massive testing in the U.S.
“I strongly advocate for the oral self-swab,” said Dr. Clayton Kazan, medical director for the L.A. County Fire Department, which is overseeing the county’s drive-thru testing program. “It may or may not be inferior, depending on the study you read, but, logistically, there is no comparison.”
But many public health officials balk at relying on the simpler tests unless scientific data convincingly shows they work as well as the accepted methods.
“In the middle of this pandemic, we don’t want to compromise, especially if people are going to use that information to decide if they’re going to follow social distancing,” said Dr. Adam Jarrett, chief medical officer at Holy Name Medical Center in Teaneck, NJ.
Nasopharyngeal samples have long been standard for diagnosing influenza and other respiratory infections because the pathogens are known to colonize the upper part of the throat behind the nose. In contrast, the simpler method being used in L.A. County – in which patients are asked to cough and then swab their cheeks and the back of their mouths – is based on a limited body of emerging research.
The Centers for Disease Control and Prevention currently calls nasopharyngeal swabs the “preferred choice” for coronavirus testing. It doesn’t recommend self-collected oral fluids, and the number of jurisdictions pursuing this strategy remains limited.
The need to collect nasopharyngeal samples by professionals dressed in protective gear represents a major obstacle. That’s why interest is rising in the use of oral samples as well as nasal swabs that can be self-administered, said Lisa Barcellos, an epidemiologist at UC Berkeley.
“It’s impossible to scale up anything that requires health professionals to do it, and with equipment that’s hard to get,” Barcellos said. The surge in demand for the specialized 6-inch swabs required for the nasopharyngeal procedure has led to critical shortages, she added.
Kazan acknowledged that nasopharyngeal sampling is considered the most trustworthy method but noted recent studies have reported promising results from oral samples. Moreover, he said, relying on self-administered techniques eliminates the danger to health care personnel and minimizes the need for personal protective equipment in short supply, like masks, face shields and protective suits.
Kazan said people who receive the tests are relieved to find that collecting secretions from their mouths is relatively quick and easy.
But to be useful, diagnostic tests must be accurate. A “false negative,” in which the test fails to detect the coronavirus, could lead someone who is infected to think they are safe and pose no danger to others.
Since the pandemic began, a growing body of research – some of which has not yet undergone peer review – has compared how accurately different sampling techniques detect the virus.
“Everybody’s looking for better ways to do this,” said Barcellos.