Saliva tests emerge as new option to diagnose COVID-19
The use of saliva tests to fill the need for diagnosing COVID-19 has its pros and cons, experts told Healio Primary Care.
“There is a shortage of nasopharyngeal swabs and, thus, a great desire to establish an alternative sampling method that does not rely on swabs,” Carey-Ann D. Burnham, PhD, D(ABMM), FIDSA, F(AAM), a professor of pathology and immunology at Washington University School of Medicine in St. Louis, said in an interview. “Nasopharyngeal swabs cause patient discomfort, whereas saliva is noninvasive.”
She also noted that saliva test samples can be obtained while still conforming to social distancing guidelines, perhaps even allowing health care workers conserve their personal protective equipment.
“Saliva test administrators may be able to use less PPE than those who use swabs,” Burnham said. “The patient could collect a sample distant from the health care provider — even in a different room — and, thus, this could reduce the PPE that is needed.”
However, Linoj P. Samuel, PhD, division head of clinical microbiology at the Henry Ford Health System in Detroit, argued that saliva test administrators should continue to use PPE.
“Some level of PPE is still important around patients suspected of COVID-19, regardless of specimen type,” he said.
Andrea Culliford, MD, FACG, a gastroenterologist at the Medical Offices of Manhattan in New York City, said that a blood sample can only be taken by a phlebotomist. But nearly any health care professional can take a saliva sample, giving health systems greater flexibility.
However, saliva tests have limitations, according to Culliford. For example, more data are needed to determine if they are as accurate as antibody titers in blood samples.
Burnham added that patients with COVID-19 can become dehydrated, making it difficult to conduct saliva tests.
In addition, Samuel said it is uncertain how best to handle saliva samples after they have been collected.
“There is still some debate as to whether we need transport media to keep the virus stable in saliva for transport prior to testing,” he said.
The Rutgers University’s RUCDR Infinite Biologics team recently announced that it received the first FDA approval of a saliva test that detects biomaterial of SARS-CoV-2, the virus that causes COVID-19.
“Doctors should look for data on [test] performance for each platform,” Samuel said. “There may be significant variability between different assays.”
Culliford said, “We usually like to see at least 90% sensitivity for the disease process being tested for and at least 90% specificity for the disease.” – by Janel Miller
Reference: Rutgers University. New Rutgers saliva test for coronavirus gets FDA approval. https://www.rutgers.edu/news/new-rutgers-saliva-test-coronavirus-gets-fda-approval. Accessed April 28, 2020.
Disclosures: Burnham reports that her laboratory has received financial support from BioFire, bioMerieux, Cepheid and Luminex. Culliford and Samuel report no relevant financial disclosures.