The CMS overpaid the University of Michigan Health System $6.2 million and it should refund the federal government, according to HHS' Office of Inspector General.
The agency reviewed claims from 2014 and 2015 and found that the hospital did not fully comply with Medicare billing requirements for 73 claims that contained errors, resulting in overpayments.
The health system did not have adequate controls to prevent the incorrect billing of Medicare claims, according to the OIG.
The health system disagreed with some of the findings and in a letter to the agency questioned what counts as overpayments.
This is the second health system in recent weeks that has been flagged for overpayments by the OIG. Last month, the agency found that Carolinas HealthCare System over billed Medicare by $1.7 million.
The audits are part of a series of hospital compliance reviews and a key focal point for the OIG, especially given the outlay of Medicare payments to hospitals. For calendar year 2015, Medicare paid hospitals $163 billion or 46% of all fee-for-service payments for the year.