Paula Mendoza, licensed vocational nurse administers a test for COVID-19 to Student Wellness Services Director Dan Nyirady. Photo courtesy of Student Wellness Services
Widespread testing has long been touted by public health officials as one of the best ways to control the COVID-19 pandemic and save lives. In January, in keeping with this guidance, La Sierra University bolstered its disease detection efforts with the rollout of new, rapid-test equipment.
On Jan. 13, 2021, the university’s student wellness services department deployed a rapid point-of-care PCR Cepheid GeneExpert Express molecular testing system. This testing system will function in conjunction with a saliva-based screening process developed last summer by virologist Arturo Diaz, who studies positive-strand RNA viruses of which the SARS-CoV-2 virus is a member. SARS-CoV-2 is the virus that causes the illness named COVID-19.
While the initial testing capacity of the Cepheid GeneExpert Express is restricted due to manufacturer limits on test cartridges, the objective is for the $32,000 machine to replace the current campus testing clinics which have been held every other week since September by PMH Laboratory Inc. based in Huntington Beach, California. The dual investment in rapid testing and the saliva-based process in Diaz’s biology lab allows the university to cast a wider net in confirming the presence of SARS-CoV-2.
Following the purchase of equipment, reagents and lab supplies, Diaz began providing twice-weekly saliva-based tests in September to student-athletes and coaches prior to practices. Dorm students who have been permitted to live on campus under health and safety protocol — a total of 79 as of the start of February — are also screened for COVID-19 via Diaz’s lab on the weeks in between the PMH Laboratory campus testing clinics. The university will begin offering weekly saliva-based testing to all staff, faculty and students on Feb. 16.
Paula Mendoza, licensed vocational nurse with Student Wellness Services processes a COVID-19 test specimen with the new PCR Cepheid GeneExpert Express molecular testing system. (Photo courtesy of Student Wellness Services)
Since the saliva-based tests lack FDA approval, they are used as a screening tool to function in concert with approved testing processes through PMH Laboratory and the new rapid-test system. Presently the Cepheid GeneExpert Express is used only to test COVID-symptomatic individuals who have permission pursuant with state guidelines to study, live or work on campus, campus members who don’t have other testing options, and to confirm positive COVID-19 tests resulting from Diaz’s saliva-based testing process.
“This new Cepheid GeneExpert Express system allows us to quickly isolate and quarantine individuals who test positive for COVID-19,” said Dan Nyirady, Student Wellness Services director. “The dual-track approach to detecting and containing COVID is critical to the health of the campus and our surrounding community.”
Daisy Pineda, a staff member in Dr. Arturo Diaz's lab, processes saliva samples for COVID-19 screening tests. Photo by Natan Vigna
As of Feb. 3, the university reported on its website two positive COVID-19 cases currently on campus, one staff member and one student. One case was first flagged by the saliva-based screening test and confirmed by PMH Laboratory, and the other detected directly by PMH. In addition to dorm students, most of who are international and out-of-state students, athletes or those with housing insecurities, a total of nine science labs and art studio classes for limited numbers of students are being held onsite during winter quarter under health and safety protocol as allowed by state guidelines issued last August.*
The Cepheid GeneExpert Express is considered to be the gold standard for diagnostic testing. It runs four tests simultaneously with one test cartridge, one for COVID plus three other diseases — flu types A and B, and for RSV, or respiratory syncytial virus, a common cause of lung and airway infections. Results are obtained in roughly 38 minutes with the entire process, beginning with the collection of a nasal swab specimen, totaling about 45 minutes.
Diaz, an associate biology professor, teaches virus research courses to undergraduates as part of the national SEA-PHAGES and SEA-GENES programs offered through the Howard Hughes Medical Institute. Following a pilot run in September, he established the COVID-19 testing lab within a laboratory at Price Science Complex where he teaches. Currently Diaz’s lab assistants deliver testing kits to the athletic department and once all the saliva samples are collected from the team members, the samples are brought to the PSC lab for processing. A centralized collection site will be established for handling campus-wide testing.
The saliva tests are simpler, easier, and less costly to administer and process than polymerase chain reaction or PCR tests, Diaz says. The saliva samples are analyzed using reverse-transcriptase loop-mediated isothermal amplification or RT-LAMP, which produces easily observed results. “If there is SARS-CoV-2 genetic material present in the saliva sample, the reaction will copy so much DNA that the pH of the solution actually changes. This turns the solution from a bright pink to a clear yellow, signaling a positive test,” Diaz said. “The entire process, from saliva collection to completion of the LAMP reaction, takes about two to two-and-a-half hours. The tests cost about $6 apiece.” The university covers costs for the tests which are free to students and employees.
The development of the saliva-based test resulted from the university’s interests in finding less-costly methods that could work in combination with the more expensive, FDA-approved PCR tests as a means to broaden its surveillance of contagious diseases.
“[We] looked for potential alternatives to survey students and faculty as frequently as possible to avoid potential outbreaks on campus,” Diaz said. “One of the keys is that we collect saliva samples instead of nasal swabs to make collection easier and safer. This is important as we want to test students, faculty and staff in a systematic and ongoing basis.”
“We are very excited to begin using our new rapid Cepheid GeneExpert Express testing machine which will greatly improve the university’s ability to detect not only COVID-19, but other diseases,” Nyirady said. “All of these investments are evidence of the significant care and concern the university holds for its campus members.”
*The La Sierra University campus moved its operations online in March 2020 and opened a handful of in-person labs and studio classes in September with options for attending online. Public sporting events were canceled with athletic team practices allowed under strict protocol.
— Darla Martin Tucker is director of Public Relations for La Sierra University; this article originally appeared on the university website.