In 1997, the Department of Justice made allegations of False Claims Act violations in four jurisdictions against roughly 145 hospitals, even though it did not have sufficient evidence to back up those claims, the General Accounting Office claims in a new report.

More than 100 of those cases, all of which involved alleged Medicare billing fraud for patient lab tests, are still pending. Of the roughly 45 cases resolved, a fair but uncertain number were dropped because prosecutors concluded that the hospitals had not violated the False Claims Act, the GAO reported.