COVID-19 saliva tests: What is the benefit?

A test that uses saliva to diagnose COVID-19 infections has been authorized by the Food and Drug Administration for emergency use. Saliva tests typically require patients to spit into a tube, making them far less invasive than the current nose and throat swab collection methods for COVID-19.

Dr. Gregory Poland, a Mayo Clinic infectious diseases expert, says that the saliva test is not only quicker and more scalable than current swab collections, but also it would lessen exposure for health care workers.

"On the plus side is the immense benefit at the population level to not have to be face to face with a health care worker, which puts two people at risk, and to mail these out and perform this kind of testing. That would be very useful," says Dr. Poland.

The saliva test could also reduce the need for use of personal protective equipment for testing and preserve personal protective equipment for use in patient care.

However, Dr. Poland says, a downside is not yet knowing the operating characteristics of the test.

"When somebody spits into a tube, it's really three different fluids. It's salivary gland fluid, It's what's called crevicular fluid that seeps out from the gums. And then it's sputum. The operating characteristics of the test are likely to be such that it won't be as sensitive as the more uncomfortable nasopharyngeal swab test. But we don't know that yet," says Dr. Poland.