The nation's largest doctors' group says about one in five payments of medical claims by commercial health insurers is inaccurate, shortchanging physicians.
The American Medical Association released its annual report card on insurers Monday. The AMA says eliminating mistakes would save doctors and insurers $17 billion a year.
The AMA rated UnitedHealthcare highest of seven commercial insurers with an accuracy rate of 90 percent.
Medicare, the government program for people 65 and older, was even better, with a 96 percent accuracy rate.
Lowest rated was Anthem Blue Cross with 61 percent. Anthem's parent company, WellPoint Inc., responded that it is increasing electronic claims processing while decreasing paper billing and now receives about nine of 10 claims electronically.
The AMA is holding its annual meeting in Chicago.