Just browsed and found this has been discussed
How would they know if you use the APP
Note: With the initial Medicare coverage ruling, there is a requirement that patients only use the Dexcom G5 Receiver to view their glucose data and not a smart phone or other device. We realize that many patients want to use their smart phone to view their glucose data and we are continuing to work with CMS regarding this decision. For now, exclusive use of the G5 receiver is the requirement for Medicare reimbursement. Dexcom has no ability to override this decision, therefore, we must advise our customers not to use the app with the Medicare product. If a patient feels it is critical to have the ability to use the app, a non-Medicare reimbursed Dexcom system is available for purchase with a prescription.