CGM Insurance Denial: Exactly What to Do Next

You Just Got Denied. Here's What to Do Right Now.

Getting a CGM insurance denial feels like a punch to the gut — especially when you know how much that sensor matters to your daily management. Take a breath. A denial is not the end of the road. In fact, insurance experts estimate that more than 40% of appealed denials are overturned. You have rights, you have time, and this guide gives you every exact step to fight back.

Step 1: Read the Denial Letter Word for Word

Your insurer is legally required to send a written Explanation of Benefits (EOB) or denial letter. Find these specific details before you do anything else:

• The denial reason code — common ones include "not medically necessary," "requires prior authorization," "step therapy not met," or "non-formulary item."
• Your appeal deadline — most plans allow 180 days from the denial date under ACA rules, but some shorten this to 60 days. Do not miss this window.
• The internal appeal process — the letter must explain how to file. If it doesn't, call the Member Services number on your insurance card immediately.

Step 2: Call Your Insurer — Use This Script

Call the Member Services number on your insurance card and say exactly this:

"My name is [NAME], member ID [ID NUMBER]. I received a denial for my continuous glucose monitor on [DATE]. I am calling to request the specific clinical criteria used to deny this claim, the name and credentials of the reviewer who made this decision, and instructions for filing a formal internal appeal. I also want to confirm my appeal deadline in writing."

Write down the representative's name, the date and time, and a call reference number. This call creates a paper trail that protects you later.

Step 3: File Your Internal Appeal Immediately

An internal appeal asks your insurer to re-review the denial. Submit these documents together:

1. A written appeal letter (sample below)
2. A Letter of Medical Necessity (LMN) from your endocrinologist or PCP — this is the single most important document. It should reference your A1C, frequency of hypoglycemic episodes, and how CGM directly impacts your safety.
3. Clinical guidelines — cite the American Diabetes Association 2024 Standards of Care, which state that CGM is recommended for all people with diabetes using insulin.
4. Your prescription and any prior CGM data showing glucose variability or hypoglycemia.

Sample Internal Appeal Letter

Date: [TODAY'S DATE]
To: [INSURER NAME] Appeals Department
Member Name: [YOUR NAME]
Member ID: [YOUR ID]
Claim/Reference Number: [FROM DENIAL LETTER]

Dear Appeals Reviewer,

I am writing to formally appeal the denial of coverage for my Continuous Glucose Monitor (CGM), specifically [DEVICE NAME/BRAND], issued on [DENIAL DATE].

This denial was coded as [INSERT DENIAL REASON]. I respectfully dispute this decision on the following grounds:

1. MEDICAL NECESSITY: I have been diagnosed with [Type 1 / Type 2] diabetes and am currently managed with [insulin therapy / multiple daily injections / insulin pump]. My most recent A1C is [X%]. I have experienced [X] documented hypoglycemic episodes in the past [timeframe], placing me at serious risk without real-time glucose monitoring.

2. CLINICAL EVIDENCE: The American Diabetes Association 2024 Standards of Care (Section 7) recommends CGM for all insulin-using people with diabetes. The device is classified as durable medical equipment (DME) under CMS guidelines and is covered by Medicare for qualifying patients.

3. SAFETY RISK: Denial of this device constitutes a direct risk to my health and safety. Fingerstick testing alone does not provide the trend arrows or alerts necessary to prevent severe hypoglycemia.

Enclosed: Letter of Medical Necessity from [DR. NAME], clinical guidelines, and supporting prescription documentation.

I request a full reversal of this denial within the required timeframe. If this internal appeal is denied, I intend to pursue an independent external review.

Sincerely,
[YOUR NAME]
[PHONE / EMAIL]

Step 4: Request an Expedited Appeal If Needed

If your health is at immediate risk without the CGM, you can request an expedited internal appeal. Insurers are required by federal law to respond within 72 hours. Use the phrase: "I am requesting an expedited appeal based on urgent medical need."

Step 5: Demand an External Independent Review

If your internal appeal is denied, you have the right to an External Appeal (also called an Independent Medical Review). An independent organization — not your insurer — reviews the case. Under the ACA, this applies to all non-grandfathered plans. For Medicare, file through the CMS appeals process at medicare.gov or call 1-800-MEDICARE. For state-regulated plans, contact your State Insurance Commissioner — they can intervene directly and are often more powerful than you'd expect.

Step 6: File a Complaint in Parallel

Don't wait for the appeal to finish. File a complaint simultaneously with:

• Your State Insurance Commissioner (find yours at naic.org)
• CMS if you have Medicare or a Marketplace plan
• Your employer's HR department if you have employer-sponsored insurance — they have leverage over the insurer you do not

While You Fight: Don't Go Without Supplies

Insurance battles can take weeks. You should not have to ration sensors or go without monitoring while you wait. MDS Diabetes (mdsdiabetes.com) carries CGM sensors, lancets, test strips, and diabetes supplies that are FSA and HSA eligible — no prior authorization required. Order directly and use your tax-advantaged health funds while your appeal is in process.

Key Deadlines Cheat Sheet

• Internal appeal: File within 180 days of denial (ACA standard) — check your letter
• Expedited appeal response: Insurer must respond within 72 hours
• Standard internal appeal response: 30 days for pre-service; 60 days for post-service
• External review request: File within 4 months of final internal denial

You are your own best advocate. A denial is a bureaucratic obstacle, not a medical verdict — and now you have exactly what you need to fight it.