COVID-19 tests that use patients’ saliva to screen for the virus are just as effective as those that use swabs collected from the nose and throat, an analysis published by JAMA Internal Medicine found.
Saliva-based tests correctly identified those infected with the new coronavirus 83% of the time, while nose-throat swab tests were 85% accurate, the review of data from 16 studies showed.
The saliva tests also were 99% accurate at identifying those negative for COVID-19, roughly the same as nose-throat swab tests, the researchers said.
The collection of saliva samples is less invasive and causes less discomfort than nasal-throat swabs.
“We now have enough evidence to support an alternative, more pleasant, easier-to-perform test for the diagnosis of COVID-19, especially in patients that are well enough not to be admitted to the hospital,” study co-author Guillaume Butler-Laporte told UPI.
“The test uses patient-provided saliva, rather than a nasopharyngeal swab, or a ‘stick in the nose,’ with almost identical accuracy,” said Butler-Laporte, an epidemiologist at McGill University in Montreal.
Analysis of nose and throat samples has become the standard in testing since the start of the pandemic last March, as the approach has been used in screening for respiratory viruses for years, according to Butler-Laporte.
Although the tests are accurate, they can cause discomfort, given that they entail inserting what is essentially a long Q-tip in the nostrils or in the back of the throat, he said.
“Given that we knew they performed well in similar viruses and diseases, such as influenza or the other types of coronaviruses, it was natural to start with [nasal-throat swab tests],” Butler-Laporte said.
“We also know that those viruses infect the upper respiratory airways, and therefore it would make sense to try and obtain a sample that is close to the site of infection,” he said.
For their analysis, Butler-Laporte and his colleagues analyzed data from 16 studies comparing the accuracy of saliva and nose-throat swab tests in the diagnosis of COVID-19.
Collectively, the 16 studies included in the analysis enrolled more than 5,900 participants, they said.
Fifteen studies included COVID-19 patients who did not require hospital care and nine exclusively enrolled those with mild or no symptoms, according to the researchers.
“Most of the data that we used in our study, which compared the two types of tests, was obtained in patients who did not require hospitalization, so it could still be that some sicker patients may benefit from more invasive types of diagnostic tests,” Butler-Laporte said.
“But for most of the patients in the community, an initial test with saliva performs just as well as the swab,” he said.