What to Do When Medicare Denies Your CGM Coverage

You Just Got Denied — Here's What to Do Next

Getting a Medicare denial for your CGM sensors or diabetes supplies is frustrating, frightening, and frankly unfair. You rely on this technology to manage your health safely — and now a piece of paper is standing between you and your device. Take a breath. Denials are not final. Medicare denials are overturned at appeal every single day, and you have clear legal rights to fight back. This guide gives you the exact steps, exact language, and exact deadlines you need right now.

Step 1: Understand Why You Were Denied (Read the Denial Notice Carefully)

Medicare is required to send you a written denial called an Advance Beneficiary Notice (ABN) or a Medicare Summary Notice (MSN). Read it carefully and look for the specific denial reason. Common denial codes include:

• Not medically necessary — Medicare doesn't believe your CGM meets coverage criteria
• Missing prior authorization — your supplier didn't get pre-approval before billing
• Incorrect diagnosis code — your provider listed the wrong ICD-10 code (should be E11.x or E10.x for diabetes)
• Supplier not enrolled — your DME supplier may not be Medicare-approved
• Step therapy not satisfied — Medicare may claim you haven't tried a required prior treatment

Knowing why you were denied tells you exactly how to appeal. A denial for "not medically necessary" requires a different response than a billing error.

Step 2: File a Redetermination (Level 1 Appeal) — Deadline: 120 Days

Your first formal appeal is called a Redetermination. You have 120 days from the date on your denial notice to file this. Do not wait — this deadline is strict.

How to file:

1. Call your Medicare Administrative Contractor (MAC) — the number is on your MSN or denial letter
2. Or mail your appeal to the address listed on the denial notice
3. Submit CMS Form 20027 (Redetermination Request Form) — downloadable at cms.gov
4. Attach a letter from your endocrinologist or primary care physician documenting medical necessity
5. Include your A1C results, hypoglycemia history, and any logs showing glucose variability

What to say when you call:
"I am calling to file a formal Redetermination request for a denied CGM claim. My Medicare ID is [number]. I received a denial dated [date] and I am within my 120-day window. I would like to confirm the correct mailing address for my appeal package and request a reference number for this call."

Step 3: Escalate to a Qualified Independent Contractor (Level 2 Appeal)

If your Redetermination is denied, you can escalate to a Qualified Independent Contractor (QIC) — an independent reviewer not employed by Medicare. You have 180 days from the second denial to file this. Use CMS Form 20033. At this stage, strengthen your package with:

• A detailed letter of medical necessity on official letterhead from your endocrinologist
• Published clinical guidelines from the American Diabetes Association (ADA) supporting CGM use
• Peer-reviewed studies showing CGM reduces hypoglycemic events and hospitalizations

Step 4: Request an ALJ Hearing (Level 3 Appeal)

If the QIC still denies you — and the amount in controversy exceeds $180 (most CGM claims do) — you can request a hearing before an Administrative Law Judge (ALJ). File within 60 days of the QIC denial using CMS Form 20034. You may bring your doctor to testify or submit written testimony. This level has a strong track record for patients with solid medical documentation.

Sample Appeal Letter for CGM Medical Necessity

[Your Name]
[Address] | [Medicare ID] | [Date]

RE: Redetermination Request — Denied Claim for Continuous Glucose Monitor (HCPCS Code A9276/A9277)

Dear Medicare Administrative Contractor,

I am writing to formally appeal the denial dated [denial date] for coverage of my continuous glucose monitoring system and sensors. I have been diagnosed with Type [1/2] Diabetes Mellitus (ICD-10: E[10/11].x) and am currently on [insulin/insulin pump therapy]. My physician has determined that CGM is medically necessary to prevent life-threatening hypoglycemic episodes and to achieve safe glycemic control.

My most recent A1C is [X%], and I have experienced [X] documented hypoglycemic events in the past [timeframe]. Enclosed please find a Letter of Medical Necessity from my endocrinologist, Dr. [Name], as well as supporting clinical literature from the American Diabetes Association confirming CGM as the standard of care for patients in my situation.

I respectfully request immediate reconsideration of this denial. Please contact me at [phone] with any questions.

Sincerely,
[Your Name]

Step 5: File a Complaint with Your State Insurance Commissioner

Even while your appeal is in progress, you can file a complaint with your State Insurance Commissioner. Visit naic.org to find your state's office. For Medicare Advantage plans specifically, you can also file a complaint directly with CMS at 1-800-MEDICARE (1-800-633-4227). These complaints create regulatory pressure and are documented in your insurer's compliance record.

Don't Go Without Supplies While You Fight

Appeals can take weeks or months. In the meantime, you still need your CGM sensors and diabetes supplies. MDS Diabetes (mdsdiabetes.com) carries a full range of CGM sensors, test strips, lancets, and diabetes management supplies — all FSA/HSA eligible with no prior authorization required. You can order directly, ship fast, and keep managing your health while your appeal moves forward. Don't let a bureaucratic delay put your health at risk.

Quick Reference: Medicare CGM Appeal Deadlines

• Level 1 – Redetermination: 120 days | CMS Form 20027
• Level 2 – QIC Review: 180 days | CMS Form 20033
• Level 3 – ALJ Hearing: 60 days | CMS Form 20034
• Level 4 – Medicare Appeals Council: 60 days after ALJ
• Level 5 – Federal District Court: 60 days after Council ruling

You have rights. You have time. And you have a clear path forward. Start with Step 1 today.