Medicare investigators in Los Angeles, using sophisticated computer technology to sift through claims data, saw an unusual pattern: A single patient had apparently undergone a diagnostic rectal-probe procedure 118 times in a year — at 21 medical facilities.

“It’s unlikely that could have occurred,” says Kim Brandt, director of program integrity at the Centers for Medicare and Medicaid Services. “This person would not have been able to sit on a plane.”

Borrowing techniques from financial and credit services, Medicare and private health insurers are increasingly “mining” claims data for suspicious patterns, comparing practitioners with their peers and larger databases of claims.