Medicare Coverage for Diabetes Supplies: Part B vs Part D Explained

Introduction: Why Medicare's Diabetes Coverage Is More Complicated Than It Should Be

More than 33% of Medicare beneficiaries — approximately 18 million Americans — have diabetes, according to the Centers for Medicare and Medicaid Services (CMS). Despite this staggering prevalence, many patients leave money on the table simply because they don't understand how Medicare's dual-track coverage system works.

Medicare coverage for diabetes supplies is divided between Part B and Part D, two programs with different cost-sharing rules, different suppliers, and different prior authorization requirements. A CGM sensor might be covered under Part B as durable medical equipment, while the insulin you put in your pump is also covered under Part B — but the same insulin purchased at a pharmacy falls under Part D. These distinctions are not academic: they determine whether you pay 20% of the cost or a flat copay, whether you need a specific type of supplier, and how much your annual out-of-pocket exposure will be.

This guide is the definitive reference for Medicare beneficiaries with diabetes, their caregivers, and anyone helping a loved one navigate the system. We cover everything from the Part B vs Part D divide to step-by-step instructions for getting a Dexcom G7 approved under Medicare.

Medicare Part B vs Part D: The Core Difference for Diabetes Supplies

Before diving into specific supplies, you need to understand the fundamental difference between these two parts of Medicare.

Medicare Part B is your medical insurance. It covers outpatient services, doctor visits, preventive care, and — critically for people with diabetes — durable medical equipment (DME). DME is defined as equipment that is medically necessary, reusable, and used in the home. Continuous glucose monitors, insulin pumps, blood glucose meters, and related supplies all qualify as DME under Part B.

Medicare Part D is prescription drug coverage. It covers medications you pick up at a pharmacy — including most insulins, oral diabetes medications like metformin, SGLT2 inhibitors, GLP-1 receptor agonists like Ozempic, and non-insulin injectables.

The critical rule to remember: if a supply is used in connection with an insulin pump, it falls under Part B. If it is purchased at a pharmacy without a pump, it typically falls under Part D.

What Medicare Part B Covers for Diabetes: A Deep Dive

Continuous Glucose Monitors (CGMs) as Durable Medical Equipment

In 2017, CMS made a landmark decision to classify therapeutic CGMs as DME, opening the door for Medicare coverage of devices like the Dexcom G6, Dexcom G7, and Abbott FreeStyle Libre 2 and 3. This was a transformative policy change for millions of Medicare beneficiaries who were previously paying out of pocket.

To qualify for CGM coverage under Part B, a beneficiary must meet the following criteria established by CMS:

• Have diabetes (Type 1 or Type 2)
• Be currently treated with insulin injections (three or more per day) OR use an insulin pump, OR have hypoglycemia unawareness or recurrent hypoglycemia requiring medical intervention
• Have documentation that the CGM is being used to make diabetes treatment decisions
• Have a face-to-face visit with their treating physician within six months prior to ordering the CGM
• Have the CGM ordered by a Medicare-enrolled physician

Importantly, CMS updated its policy in 2023 to remove the requirement that a beneficiary must perform a minimum number of fingerstick tests per day — a change that broadened access significantly.

Insulin Pumps Under Part B

External insulin infusion pumps are covered under Part B as DME when the beneficiary has Type 1 diabetes or Type 2 diabetes that cannot be controlled with oral medications and subcutaneous insulin injections. The physician must document that the patient requires intensive insulin management and that the pump is medically necessary. Tubeless patch pumps like the Omnipod may also qualify — check with your specific supplier for current coverage status.

Blood Glucose Meters and Test Strips

Medicare Part B covers one blood glucose meter per beneficiary, plus test strips and lancets with quantity limits. Beneficiaries on insulin typically qualify for up to 300 test strips per 3-month period; those not on insulin may receive fewer. You must purchase from a Medicare-approved DME supplier for coverage to apply.

What Medicare Part D Covers for Diabetes

Insulin at the Pharmacy

The Inflation Reduction Act of 2022 capped Medicare Part D insulin costs at $35 per month per covered insulin beginning January 1, 2023. This applies to all Medicare Part D plans for covered insulins, regardless of the plan's deductible. This is a significant financial relief for the estimated 3.3 million Medicare beneficiaries who use insulin.

Oral and Non-Insulin Injectable Medications

Medications such as metformin, sulfonylureas, DPP-4 inhibitors, SGLT2 inhibitors, and GLP-1 receptor agonists like Ozempic and Trulicity are covered under Part D. Coverage depends on your specific plan's formulary. GLP-1 medications are often placed on higher tiers (Tier 3 or 4), making prior authorization and step therapy requirements common barriers. Always review your plan's formulary during the Annual Enrollment Period (October 15 – December 7) to ensure your medications are covered.

How Much Will You Pay? Medicare Cost-Sharing Explained

Part B Cost-Sharing for DME

Under Medicare Part B, after you meet your annual deductible (which is $240 in 2024), Medicare pays 80% of the approved amount for covered DME. You are responsible for the remaining 20% — with no annual out-of-pocket cap in original Medicare. This 20% can add up quickly. For example, if your CGM supplies cost $2,000 annually under the Medicare-approved amount, your share would be $400 per year, plus the deductible.

The Importance of Supplemental Coverage (Medigap)

Because Part B has no out-of-pocket maximum and you are exposed to 20% coinsurance indefinitely, Medigap (Medicare Supplement Insurance) is critically important for beneficiaries who rely on expensive diabetes supplies. Medigap plans F, G, and N are among the most popular and can cover all or most of your 20% coinsurance. If you have a Medigap plan, your CGM, pump supplies, and test strips may effectively cost you nothing after the deductible.

Medicare Advantage (Part C) and Diabetes Extras

Medicare Advantage plans (Part C) are required to cover everything original Medicare covers, but many go further. Some Medicare Advantage plans offer:

• Reduced or $0 copays for DME including CGMs
• Broader formularies for diabetes medications
• Coverage for over-the-counter diabetes supplies through supplemental benefits
• Gym memberships and wellness programs relevant to diabetes management
• Meal delivery benefits post-hospitalization for diabetic patients

However, Medicare Advantage plans use networks, may require prior authorizations more frequently, and formularies vary widely. Always compare plans using Medicare's Plan Finder tool at medicare.gov before enrolling.

Step-by-Step Guide: Getting the Dexcom G7 Approved Under Medicare

The Dexcom G7 is one of the most widely used CGMs and is covered under Medicare Part B as a therapeutic CGM. Here is exactly how to get it approved:

1. Confirm eligibility: Ensure you meet CMS therapeutic CGM criteria — primarily that you have diabetes and use insulin three or more times daily or use an insulin pump, or have documented hypoglycemia issues.
2. Schedule a face-to-face visit: You must have a documented in-person or qualifying telehealth visit with your treating physician within 6 months before the CGM order is written. The physician must document the medical necessity of the CGM in your chart.
3. Get a written order: Your physician writes a detailed prescription/order specifying the CGM system (Dexcom G7), including the device, sensors, and transmitters. The order must include your diagnosis code (ICD-10: E11.x for Type 2, E10.x for Type 1), insulin usage documentation, and the treating physician's NPI number.
4. Choose a Medicare-approved DME supplier: The Dexcom G7 must be obtained through a Medicare-enrolled DME supplier — not a retail pharmacy. Dexcom has its own Medicare fulfillment option; you can also use suppliers like Byram Healthcare, Edgepark, or others. Using a non-approved supplier means Medicare will not pay.
5. Submit prior authorization if required: Most CGM claims do not require prior authorization under original Medicare Part B, but some Medicare Advantage plans do. If your plan requires prior auth, your supplier and physician will coordinate this. Required documentation typically includes: office visit notes, lab values (HbA1c), insulin regimen details, and a letter of medical necessity.
6. Verify assignment: Ensure your DME supplier accepts Medicare assignment, meaning they agree to Medicare's approved payment amount. If they don't, you may be charged more.
7. Receive your supplies: Once approved, you will receive your Dexcom G7 receiver and initial sensors. Replacement sensors and transmitters are shipped on a scheduled basis. Keep records of all shipments and payments.
8. If denied, appeal: Medicare CGM denials are common and often overturned on appeal. You have the right to a Redetermination (Level 1 appeal) within 120 days of the denial. Gather supporting documentation from your physician and submit a detailed appeal letter.

Prior Authorization: What You Need to Know

Original Medicare (Parts A and B) has historically not required prior authorization for most CGM and DME claims, though this is changing. CMS has introduced a prior authorization program for certain high-cost DME items. Medicare Advantage plans, however, routinely require prior authorization for CGMs, insulin pumps, and branded medications.

For prior authorization, typical required documents include:

• Completed Certificate of Medical Necessity (CMN) form — especially for insulin pumps (Form CMS-484)
• Physician's detailed office notes documenting the medical necessity
• Lab results including HbA1c values
• Documentation of current insulin regimen
• History of hypoglycemic episodes if applicable

Work closely with your physician's office staff, as they are most familiar with the documentation requirements for your specific plan.

Medicare Coverage for Diabetes: Preventive Services

Medicare covers several preventive services for diabetes at no cost to the beneficiary (no deductible or coinsurance) when provided by a Medicare-enrolled provider:

• Diabetes screening tests: Up to two per year for at-risk beneficiaries
• Medical Nutrition Therapy (MNT): Three hours in the first year, two hours per year after that
• Diabetes Prevention Program (DPP): For beneficiaries with prediabetes, delivered by a CDC-recognized organization
• Annual Wellness Visit: Includes diabetes risk assessment

Tips to Maximize Your Medicare Diabetes Benefits

• Review your Part D formulary every year during the Annual Enrollment Period. Drug tiers and costs change annually.
• Use Medicare's Extra Help program if you have limited income — it can dramatically reduce your Part D drug costs.
• Ask your physician to document everything. Medical necessity documentation is the most common reason CGM and pump claims are denied.
• Use Medicare-assigned suppliers only. For all DME including CGMs, using a non-participating supplier means you pay the difference.
• Consider Medigap Plan G if you are newly Medicare-eligible — it covers your 20% Part B coinsurance and can make your diabetes DME effectively free after the deductible.
• Keep your insulin properly stored. Whether covered under Part B (pump insulin) or Part D (pharmacy insulin), protecting your insulin investment is critical — especially when traveling.

Product Recommendation: Protecting Your Insulin Investment While Traveling

Medicare covers your insulin, but it doesn't protect it from heat damage while you travel. Insulin exposed to temperatures above 80°F can lose potency rapidly — rendering your expensive, Medicare-covered medication useless. The VIVI CAP Insulin Cooler — TSA Approved, available at mdsdiabetes.com for $125.00, is the perfect solution for Medicare beneficiaries who travel.

The VIVI CAP uses patented passive cooling technology — no batteries, no ice, no refrigeration required. It keeps your insulin pens and vials at safe temperatures for up to 60 hours, making it ideal for flights, road trips, and outdoor activities. It is TSA-approved, meaning you can carry it through airport security without hassle. For GLP-1 users on Ozempic or Trulicity — medications typically covered under Part D — the VIVI CAP also protects these high-cost injectables from temperature damage. Protecting your Medicare-covered medications from heat damage is one of the smartest investments a diabetic traveler can make. Shop the VIVI CAP at mdsdiabetes.com.

Frequently Asked Questions: Medicare Diabetes Supplies Coverage