PITTSBURGH (KDKA) — Batching tests for coronavirus could be the next way to identify and stamp out potential hotspots, something called pool testing.

“I think it’s a great idea,” says Dr. James Deangelo, an immunologist at Allergy and Clinical Immunology associates.

It casts a wide net, pooling samples from groups of three to 50 people.

If the group test is negative, you’re done. But if it’s positive, you’ll need individual diagnostic tests to figure out who has the virus.

“You have to follow people. You have to have some way of tracing,” says Dr. Deangelo.

The idea is to find people who are asymptomatic or pre-symptomatic before they spread the disease to others.

It’s most useful in groups where the expected frequency is low, for example, a business or summer camp.

If a pooled test is positive, everyone in the group must isolate while individual test results come back.

This has implications for the group, for instance, if you test the staff at a doctor’s office.

“If you quarantine every single nurse, who’s going to take care of the sick?” Dr. Deangelo asks. “It’s a tricky issue, and that’s where rapid testing comes into play.”

There are some other issues with this approach. Someone who is no longer infectious, but still has viral particles will turn the group sample positive. And someone very early in the illness may not have enough virus particles to turn the group sample positive.

“You’re going to miss some,” Dr. Deangelo said.

Even so, pool testing is being considered for back-to-school and back-to-work campaigns because you can test more people and test more frequently.

“I think it’s more practical than what we’ve been doing, which is no testing at all,” Dr. Deangelo says.

Other countries do pool testing, but federal rules limit availability in the US. The FDA is trying to work out how to go about pool testing nationally.

Dr. Maria Simbra