Thai researchers developing saliva test for COVID-19

Thai researchers said last week they have had success in developing a test that can detect the presence of COVID-19 in a person’s saliva, and are working on another that relies on saline instead of costly chemical reagents.

Meanwhile, the government said that it would double the number of tests it administers for members of at-risk groups next month. Public health officials have said increased testing would help to track and contain the virus to prevent mass outbreaks as the economy reopens.

In the United States, Dr. Deborah Birx, the coronavirus response coordinator at the White House, said last week that a “breakthrough” in testing is needed to support reopening. A saliva test could be one possible breakthrough.

Dr. Siriorn Watcharananan, a member of the research team at Mahidol University that developed the saliva test, said in a press conference that she and her colleagues had tested it on some of the 200 samples taken through various methods including throat swabs and saliva. Mahidol is Thailand’s premier medical university.

Tests using throat swabs identified 19 positive cases, while the tests using saliva found 18 cases, she said. The saliva tests produced 84.2 percent sensitivity, 98.9 percent specificity, and 97.5 percent agreement.

“This is our first achievement, and we are going to do more to cut down expenditure for the virus test,” Dr. Siriorn said. “We are going to develop saline testing instead of using expensive chemicals.”

Currently, the reverse transcription-polymerase chain reaction (RT-PCR) is the most widely used method to check and confirm COVID-19 infections. However, those test kits are in short supply and are costly, and the kit’s throat swab method puts medical staff at high risk of infection, Dr. Siriorn said.

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