Cal Poly faculty develops COVID-19 saliva test they say is more effective than nasal swab testing

Mar 5, 2021

Cal Poly is now using in-house COVID-19 testing methods, and has transitioned away from third-party, Avellino Labs, which administered nasal swab testing.

Microbiology Professor Dr. Pat Fidopiastas said Cal Poly’s saliva lab tests multiple samples in batches. If a batch tests positive, they can test to find which individual in that batch has the coronavirus.

“The saliva group will get five individual saliva samples and they’ll pull them into a single, and then they’ll get that reaction, and so if they get a positive, they just have to deconvolute those five and test individually.” Fidopiastas said.

The efficiency of the batch testing process and the fact that testing is in-house, makes the turnaround time for test results a lot faster.

Associate Professor Dr. Nathaniel Martinez worked with a team of faculty members to develop the saliva test and said the resulting process takes less than 24 hours.

“In a perfect world if we had a limited number of samples, from the acquiring the samples to resulting. It takes us about 4 1/2 hours” Martinez said.

Martinez also said this new testing method is very sensitive to the virus, so it is able to track how much virus is in a sample. And those working in the lab can gauge where students are in the infection process.

Cal Poly is also testing the wastewater around campus, so they can trace the exact locations where positive COVID-19 tests originate.

Scientists at the university are currently taking samples from different manholes on campus that contain waste from about 500 to 1,500 students per sample.

Doctor Fidopiastis said Cal Poly’s wastewater testing works in conjunction with the saliva labs, adding an extra layer of monitoring.

“If I get a hit here that's significant, what I can then do is go downstairs and tell them that P-C-V building 171 is positive and it's significant, they can go in with their saliva and then test everyone in the building.” Fidopiastas said.

Cal Poly Landscape Architecture senior Kathleen Dempsey said she thinks spitting into a tube for a saliva test is more efficient.

“In terms of how long the process took, it was a lot faster than the nasal swab. It was just kind of a one step process” Dempsey said .

Assistant Professor Dr. Jean Davidson, who helps out in the COVID-19 lab, says that testing more frequently will help the university open sooner

“If we can get robust testing and show these trends of really low rates...everyone will feel more comfortable going back” Davidson said.

More information about Cal Poly’s COVID-19 response can be found at the university’s website.