UW-Madison researchers have developed an experimental saliva test for COVID-19 that they say could be quicker, cheaper and easier to use than the nasal swab test most people take to see if they have the coronavirus.
The saliva test, which has been tried out on volunteers at three UW-Madison sites and a local elementary school, involves spitting into a tube and produces results in hours. Results from the nasal swab test, which can include probing deep into the nose, can take days or weeks.
"This sort of testing, if it is successful and can be expanded, offers hope that schools and workplaces could receive rapid turnaround testing to assist in the complex decision of managing education during the outbreak with a test that is still sensitive enough to catch the people who are contagious, but exceptional in terms of accessibility, cost and turnaround time," David O'Connor, a UW-Madison researcher who helped develop the test, said in a statement.
"Recent studies show that frequent, repeated testing is key to detecting infected people quickly," said Tom Friedrich, another campus researcher involved in the project. "Because people can be contagious before they show symptoms of COVID-19, rapid testing can allow them to isolate and protect others before they even realize they are infected."
The scientists, from UW-Madison's AIDS Vaccine Research Laboratory, are studying whether the test can be administered frequently and efficiently. The test has not been approved for clinical diagnosis.
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Most testing to detect the virus that causes COVID-19 uses a chemical process called polymerase chain reaction, or PCR, to make copies of the genetic material in a small sample so they are easier to identify. The UW-Madison group uses a different method, called reverse-transcriptase loop-mediated isothermal amplification,or RT-LAMP, to amplify the identifiable parts of virus available in saliva samples.
RT-LAMP is easier to set up than PCR and doesn't require specialized instrumentation, O'Connor said. "We realized that this sort of testing might be more appropriate for places like workplaces, schools and nursing homes that might require on-site, frequent, repeated testing," he said.
RT-LAMP also uses different chemicals than the PCR process, for which supplies have been stretched thin.
David Beebe, a UW-Madison pathology professor, and Salus, a Madison-based spinoff company he helped create in 2013, helped design an extraction process to make the RT-LAMP test more accurate with a small saliva sample.
More than 500 tests have been conducted on volunteers at the AIDS Vaccine Research Laboratory, UW — Madison Athletic Department, the Wisconsin National Primate Research Center and at Eagle School in Fitchburg, where staff, not students, have been involved.
Two positive cases have been found, along with one that may be a false positive. The results are checked with standard PCR testing.
Dawn Dudley, a UW-Madison scientist involved in the project, said the saliva test could be appealing for widespread use.
"Collection is more comfortable, which is especially important if you are getting tested twice a week and important for children," she said. "Swabs can be quite invasive and somewhat damaging over time. Spitting into a tube? Not so bad."
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