| Typical PA Decision Time | 3β14 business days |
| Urgent PA Decision Time | 24β72 hours |
| Appeal Window | 30β180 days (varies by payer) |
| Appeal Overturn Rate | ~40% of appealed denials |
| Medicare Face-to-Face Requirement | Within 6 months of CGM order |
| Average Monthly CGM Cost (No Insurance) | $300β$400+ |
Key Takeaways
- Most insurers require prior authorization (PA) before covering a CGM device or supplies.
- Documentation of diabetes type, treatment history, and hypoglycemia episodes is critical.
- Denials can be appealed β over 40% of appealed PA decisions are overturned.
- Medicare covers CGMs under the Durable Medical Equipment (DME) benefit with specific criteria.
What Is CGM Prior Authorization?
Prior authorization (PA) is a requirement by health insurers that a prescriber obtain approval before a patient receives a specific medication or device. For continuous glucose monitors (CGMs), PA is nearly universal across commercial insurance, Medicare Advantage, and Medicaid plans. Without approval, the patient bears the full out-of-pocket cost, which can exceed $300β$400/month for sensors alone.
Who Qualifies for CGM Coverage?
Eligibility criteria vary by payer, but common requirements include:
- Diagnosed Type 1 or Type 2 diabetes requiring insulin
- Three or more daily insulin injections or use of an insulin pump
- History of hypoglycemia unawareness or frequent low blood sugar episodes
- Inadequate glycemic control (A1C above target despite treatment)
Medicare specifically requires the prescribing provider to be actively managing the patient's diabetes and to have a face-to-face visit within 6 months of the CGM order.
Step-by-Step PA Approval Process
Step 1: Obtain a Prescription
Your endocrinologist or primary care physician submits a detailed prescription specifying the CGM device, frequency of use, and medical necessity.
Step 2: Gather Supporting Documentation
Insurers typically require: recent A1C results, blood glucose logs, history of hypoglycemic events, current diabetes medications, and a Letter of Medical Necessity (LMN) from the prescriber.
Step 3: Submit the PA Request
The prescriber or DME supplier submits the PA request electronically or by fax. Most decisions are returned within 3β14 business days; urgent requests may be processed within 24β72 hours.
Step 4: Respond to Additional Information Requests
Insurers may request peer-to-peer review β a direct call between your doctor and the insurer's medical reviewer. This step significantly increases approval rates.
Common Reasons for Denial
- Incomplete documentation or missing LMN
- Diabetes type or treatment regimen doesn't meet criteria
- CGM model not on the formulary
- Face-to-face visit requirement not met (Medicare)
How to Appeal a Denial
If denied, you have the right to appeal. File a formal appeal within the insurer's deadline (typically 30β180 days). Include additional clinical evidence, peer-reviewed literature supporting CGM use, and a revised LMN. An external independent review is available if internal appeals fail. Patient advocacy organizations like JDRF and ADA offer free appeal letter templates.
PA Requirements by Payer Type
| Payer | PA Required? | Key Criteria |
|---|---|---|
| Commercial Insurance | Usually Yes | Insulin use, A1C, hypo history |
| Medicare Part B | Yes | Therapeutic CGM criteria, face-to-face visit |
| Medicare Advantage | Yes | Plan-specific; often stricter |
| Medicaid | Varies by state | Often Type 1 only; expanding |
Tips to Maximize Approval Odds
- Ensure your provider documents hypoglycemic episodes with dates and severity
- Request a peer-to-peer review proactively
- Confirm the CGM brand is on your plan's formulary before submitting
- Work with a DME supplier experienced in CGM PA submissions
MDS Diabetes offers a range of CGM supplies and accessories compatible with major devices including Dexcom, Libre, and Medtronic, with staff experienced in navigating insurance requirements.