According to an OIG report, “Questionable Billing for Medicare Part B Clinical Laboratory Services,” Medicare allowed $1.7 billion for clinical laboratory claims in 2010 associated with eight types of “questionable billing.” Such indicators of questionable billing identified by the OIG include: claims for beneficiaries with no associated Part B service with ordering physician; claims with beneficiaries living more than 150 miles from the ordering physician; duplicate lab tests; claims with ineligible or invalid ordering-physician numbers; claims with compromised beneficiary, ordering-physician, or lab provider number. More than 1,000 labs had unusually high billing for five or more measures of questionable billing for Medicare lab service, and almost half of these labs were located in California and Florida. The OIG notes that while “some of this billing may be legitimate, all labs that exceeded thresholds on five or more measures of questionable billing may warrant further scrutiny.” The OIG recommends that CMS: review the labs identified as having questionable billing and take appropriate action; review the effectiveness of existing program integrity strategies; and ensure that existing edits prevent claims with invalid and ineligible ordering-physician numbers from being paid. CMS concurred with these recommendations.