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What Is Pool Testing?
U.S. leaders are considering a new strategy for more efficient Covid-19 surveillance
Health experts including Dr. Anthony Fauci have mentioned in recent interviews that U.S. leadership is considering a strategy called “pool testing” or “batch testing” as an efficient way to test large swaths of people for Covid-19.
Dr. Deborah Birx, the coordinator for the White House’s coronavirus task force, said recently that “pooling would give us the capacity to go from a half a million tests a day to potentially 5 million individuals tested per day.”
How does it work?
On a basic level, pool testing is a way to do disease surveillance without the need to run tests for every individual person (though you still need their samples). It’s when samples from multiple people — like say, coronavirus nasal swabs — are tested together in a single tube. Even though the samples are mixed together, the test provides a single result for that grouping of samples.
One of the best explanations of how it works logistically is from Scientific American:
Group testing is a numbers game. Let’s say you are examining 100 people, and one of them is positive. Normally you would do 100 diagnostic tests, searching for genetic material from the virus in each individual. But with group testing, you can divide those 100 people into five groups of 20. That gives you five pools with 20 samples, and you use one test per pool. If the first four sample pools test negative, you have eliminated 80 people with four tests. If the last pool tests positive, you retest each sample in that last pool individually to identify the one with the disease. In the end, you did 25 tests instead of 100.
While the samples are mixed for the test, ideally there’s still enough initial samples from each person to run individual tests if needed rather than asking people for samples a second time.
The concept of pool testing is credited to Robert Dorfman and David Rosenblatt, economists who, during World War II, developed the idea as a way to detect draftees with syphilis. Blood samples of men were tested together, and if all the tests came back negative, the men were deemed healthy. If a group test was positive then every…
