College shifts to pooled testing model

A+sign+of+the+COVID+testing+site+of+Emerson+College+and+Tufts+University.

Photo: Hongyu Liu

A sign of the COVID testing site of Emerson College and Tufts University.

By Frankie Rowley, Deputy Express Editor

Emerson introduced a pooled testing model for all community members this week, a process administrators hope will streamline the college’s testing process. 

“The College is utilizing this method to mitigate testing costs,” wrote Associate Vice President for Campus Life and “COVID Lead” Erik Muurisepp in a Thursday morning email. “It is more environmentally-friendly, and the College is expecting a relatively lower rate of infection overall due to the current state of the pandemic.” 

Under the new testing model, individual samples will be collected in a group of ten to be tested together. The pooled model yields negative, inconclusive, invalid or unsatisfactory results, and those who receive inconclusive results will be required to test again, individually within 24 hours. The system in place prior to pooled testing saw each sample tested individually, returning a negative, positive or invalid result. 

“Pooled testing is a model that K-12 has used for some time,” said Muurisepp in a September interview. “They’ve been able to get more testing done with less resources, through streamlining the process.”

If an inconclusive result is received, community members must report back to Tufts Medical Center within 24 hours to take an individual PCR test. If an unsatisfactory or invalid result is received, another pooled test must be taken within 24 hours. All unvaccinated individuals must quarantine until they get their results. 

Get This Week's News

All the big stories delivered to your inbox every Thursday morning 

The model’s accuracy is dependent on how rapidly COVID-19 is spreading in a given area, according to the Centers for Disease Control and Prevention. The agency explained that because pooled testing requires the mixing of samples and different samples contain different amounts of “viral genetic material”—mucus from the nose or throat—pooled tests cannot ensure the diagnostic accuracy of an individual sample and has a higher risk of false-negative results. 

“In general, the larger the pool of specimens, the higher the likelihood of generating false-negative results,” read the CDC article. 

Under the new system, community members will continue weekly testing at the Tufts Medical Center facility on Kneeland Street and Harrison Avenue—but instead of tapping their IDs at one of the three Emerson-designated stations, they will instead report to a “pooled testing area” and place their swabs into a large test tube after administering their test. 

Muurisepp explained that the new model reduces processing costs, as the college no longer has to pay for each individual test conducted. During the 2020-21 school year, Emerson spent $5 million on testing. 

However, a study conducted by the Nebraska Public Health Laboratory in April 2020 found the cost effectiveness of the model decreases as the positivity rate in a given area increases. 

“As the incidence of COVID-19 increases the cost savings of a pooling strategy decreases because more pooled tests will return positive results and those specimens will need to be retested individually to determine which individual(s) are positive,” it states. 

The model will be introduced to different elements of the Emerson communities in stages, according to Muurisepp. Currently, faculty, staff, and vendors are being tested under the pooled testing model. Students are still testing individually and will begin testing under the pooled model on Nov. 1, according to an email sent out by Muurisepp Thursday morning. 

“That will be happening slowly over the next few weeks,” Muurisepp said. 

The college initially planned to roll out the new system on Sep. 7, according to a community-wide email sent five days earlier. That date came and went, and in a COVID update on Sep. 15, Muurisepp stated that the transition to pooled testing would instead be assessed “in the coming weeks.”

The original date coincided with a spike in COVID-19 cases at the beginning of the fall semester; in the two weeks before Sep. 7, Emerson reported 21 positive COVID-19 tests and a positivity rate of 0.24 percent—the highest recorded in a two week period. 

Muurisepp, however, stated that the delay was not brought on by the surge.

“It was delayed because the process was [still] being worked out,” he said. “Seeing some other institutions roll it out, we needed to make sure we could do it appropriately.”

Muurisepp did not attribute these logistical challenges to either Emerson or The Broad Institute, which is responsible for providing and processing tests for a number of colleges in the Boston area. For its part, the Broad Institute has already overseen the pooled testing of hundreds of Massachusetts schools since February; as of Sept. 14, it had processed approximately 170,000 testing pools, representing over 1.1 million swabs of K-12 students, according to its website.