Shares of CardioNet Inc. plunged Wednesday after the heart device maker said the U.S. Department of Justice is investigating allegations CardioNet may have overcharged Medicare. THE SPARK: CardioNet disclosed Tuesday that it received a civil investigative demand from the Justice Department. According to the company, the agency said it is looking into allegations CardioNet used inappropriate diagnostic codes when filing for reimbursement from the Medicare program. If the company used the wrong reimbursement codes, Medicare may have overpaid the company.
