Federal auditors say Abbott Northwestern Hospital should refund $8 million in estimated overpayments for services that the Minneapolis-based medical center wrongly billed to the federal Medicare program, according to a report released Thursday.
Auditors looked at a sample of billing records during 2013-14 and alleged a variety of errors, including bills to Medicare for patients who didn't meet the program's criteria for acute inpatient rehabilitation services.
Abbott Northwestern's parent company, Allina Health System, disputed the audit findings, which next go to the federal Centers for Medicare and Medicaid Services (CMS) for a final ruling. In a letter that also was released Thursday, an Allina official said the report includes numerous factual and legal errors that "combine to overstate significantly the amount of overpayments."
Auditors, however, said they stood by their conclusions.
"The hospital did not have adequate controls to prevent the incorrect billing of Medicare claims," the report states. "On the basis of our sample results, we estimated that the hospital received overpayments of at least $8,038,356 for the audit period."
The audit from the Office of the Inspector General (OIG) at the U.S. Department of Health and Human Services is part of an ongoing series of hospital compliance reviews being conducted at medical centers across the country. The federal Medicare program typically is the single largest source of payments for hospitals.
Over the past year, OIG has released 15 compliance reports that use computer matching, data mining and analysis techniques to identify certain types of hospital claims that could be out of compliance with Medicare billing rules.
Among the 15 reports, the largest overpayment alleged was $14.2 million at a hospital in New York; the smallest was $41,771 at a hospital in Tennessee.