Doctors who bill the federal government for a lot of services may be gaming the system, but there also may be a reasonable explanation. Aslan Alphan/Getty Images hide caption

itoggle caption Aslan Alphan/Getty Images

Walter Bianco's liver is severely damaged by hepatitis C, but insurers had refused to pay for the medications that could cure him. Alexandra Olgin for NPR hide caption

itoggle caption Alexandra Olgin for NPR

Walter Bianco's liver is severely damaged by hepatitis C, but insurers had refused to pay for the medications that could cure him. Alexandra Olgin for NPR hide caption

itoggle caption Alexandra Olgin for NPR

Data released Wednesday about Medicare payments to doctors in 2012 have raised questions, but some experts warn against drawing "sweeping conclusions" from the numbers. iStockphoto hide caption

itoggle caption iStockphoto

House Speaker John Boehner of Ohio leaves the House chamber on Capitol Hill in Washington, after House Republicans passed a measure Friday that would overhaul the system Medicare uses to pay doctors. J. Scott Applewhite/AP hide caption

itoggle caption J. Scott Applewhite/AP

A snippet of the data ProPublica obtained from the federal government about Medicare Part D, the prescription drug benefit for seniors. ProPublica hide caption

itoggle caption ProPublica