What is pooled COVID-19 testing?

One of the most important tools for tracking the epidemic and preventing outbreaks of COVID-19 is to test as many people as possible. This requires a lot of time and materials, and can lead to backlogs. In order to make the process more efficient, some places are considering using sample pooling for diagnostic testing

How does it work?

Pooled sample testing means using a single test for several people. Say you have 100 people, and you expect only 2 or 3 of them will be positive. You can group (pool) samples into batches of 10, and run 1 test on each of these pooled samples. Each negative test means those 10 people are not infected with COVID-19. If the test is positive, those people will need to be tested individually in order to determine who among those 10, might be infected. In the end, you will likely run only 30 to 40 tests instead of 100.

What are the benefits?

Pooled sample testing can help labs get results back to people faster. It can also reduce the number of supplies, like chemical reagents, that are needed to run the tests. This is helpful because some supplies continue to remain in short supply.

What are potential drawbacks?

Pooled testing is most effective when you expect that the number of positive cases in the community will be low. If lots of people are infected, then pooled testing isn’t efficient, you would end up testing everyone in addition to the pooled sample testing to figure out who is positive. It’s also important that it is easy to get in touch with people who are positive so that they can be told of their results and to quarantine. Universities, workplaces, and small neighborhoods, for example, are great places where people are easy to get in touch with to give results and perform contact tracing.

Looking ahead

Many countries are now using pooled sample testing, and in late July, Quest Diagnostics in the U.S. received FDA approval to start using a pooled sample testing protocol. Pooled testing is an important step towards both preserving important testing resources and reducing outbreaks of COVID-19. 

 

Last update: August 3, 2020, 07:40 pm ET 

Science review: ERS, JSS