In a study where people got full-body MRI scans for research, about 1 in 3 were told they had some unexpected health finding that might need attention.

When people get full-body scans or lab tests and are told about unexpected results—even if those results might not mean anything—they end up getting more biopsies, especially when the scan findings are shared. This might lead to too many medical tests that aren’t really needed.

A team of experts from different fields can help decide which unexpected health findings from a full-body MRI scan should be told to the person being scanned—and they got it right about 8 out of 10 times.

When doctors scan someone’s whole body for research, they sometimes find unexpected things — and more than half the time, they can’t tell if those things are harmless or dangerous without doing more tests.

When doctors do full-body scans for research, less than half a percent of unexpected findings turn out to be serious enough to need urgent medical attention.

When doctors tell patients about unexpected findings on a full-body MRI scan, it leads to over three times more biopsies that find cancer—but even then, very few actual cancers are found, so it might not be worth the hassle and cost.