A federal lawsuit accusing the Mayo Clinic of fraudulent billing was unsealed last week, just one day after the U.S. Department of Justice joined the suit.

Originally filed in November 2007 by David Ketroser, who is licensed to practice both medicine and law in Minnesota, the lawsuit claims that “over the course of the last 10 years, Mayo has routinely billed Medicare, Medicaid, and other federally sponsored health care programs for surgical pathology services that have not been performed.”

The complaint also accuses the Rochester-based Mayo Clinic of violating the U.S. False Claims Act by discarding some types of histopathology slides within three days after they are prepared and examined. The College of American Pathologists (CAP), which accredits clinical laboratories under the federal Clinical Laboratory Improvements Act, requires that such slides be kept for 10 years.

According to the complaint, the Mayo Clinic made false representations about the procedures it follows for histopathology slides in order to gain CAP accreditation. The Mayo Clinic allegedly indicated to CAP that it prepares and examines histopathology slides the day after an exam takes place-which the complaint says is not the case. The complaint cites two specific cases in which slides were not prepared and examined the day after the patient exams took place.

The Justice Department indicated in a September 21 court filing that it intends to intervene in the allegation that the Mayo Clinic billed for services that were not performed. The department will not become involved, however, in the claims that the Mayo Clinic improperly obtained laboratory accreditation and failed to retain histopathology slides for the appropriate time period.

In a Tuesday e-mail, Mayo Clinic spokesman Bryan Anderson said that the billing-related claim stemmed from an inadvertent error that the Mayo Clinic made and later rectified.

“Upon discovering a billing error in 2007, Mayo corrected it and voluntarily refunded $242,711 to the federal government. The error was identified and corrected long before Mayo became aware that a sealed complaint had been filed and well before Mayo was notified that the Department of Justice was evaluating whether to become involved in the complaint,” Anderson said in the e-mail. “Mayo has fully complied with the law, and we believe our response to the billing error and our approach to surgical pathology represents a 'best practice.'”

The Department of Justice indicated in the September 21 court filing that it intends to file its own complaint within 90 days.

The Mayo Clinic treats more than half a million people each year and operates two of Minnesota's largest hospitals based on number of available beds-Saint Mary's Hospital and Rochester Methodist Hospital. It has sites in Rochester; Jacksonville, Florida; and Scottsdale and Phoenix, Arizona. The Mayo Clinic is Minnesota's second-largest employer, employing 37,647 of the state's residents as of June.