To get insurance to pay for a glucose monitor, you generally need to confirm your plan covers continuous glucose monitors, meet the insurer’s medical necessity criteria, have your doctor submit documentation and a prior authorization request, and appeal in writing if the claim is denied. Without coverage, a CGM runs roughly $160 to $500 per month, so the paperwork is worth the effort even when it feels like a second job.
Confirm What Your Plan Actually Covers
Start with your summary of benefits and coverage. It will tell you whether CGMs are included and how costs are split. Most private insurers classify CGMs as durable medical equipment, but some route them through pharmacy benefits instead. That distinction changes which deductible applies, what your copay looks like, and which supplier you’re allowed to use.
Call the number on the back of your insurance card and ask three specific things: whether CGMs are covered under DME or pharmacy, what the clinical criteria are, and whether prior authorization is required. Ask them to point you to the clinical policy document, which spells out exactly what the insurer expects to see. Most plans publish these online.
Check the cost-sharing details before you order anything. You’ll usually have to meet an annual deductible first, then owe coinsurance (often 20% to 30%) or a flat copay. Some plans cover only specific brands or models, so confirm that the device your doctor recommends is on the approved list.
Meet the Medical Necessity Criteria
Insurers don’t cover CGMs for anyone who asks. A common private-plan requirement is that you use insulin multiple times a day or wear an insulin pump. Some plans also require documented low blood sugar episodes or evidence that fingerstick testing alone isn’t controlling your glucose.
Medicare’s rules are broader than many people realize. You qualify under Part B if you have diabetes and either use insulin or have a documented history of problematic low blood sugar episodes.1Medicare.gov. Continuous Glucose Monitors For beneficiaries who don’t use insulin, Medicare wants documentation of recurrent level 2 hypoglycemic events (blood sugar below 54 mg/dL) plus evidence that your treatment plan was already adjusted at least once before the most recent episode. A single level 3 event, where you needed someone else’s help to treat the low blood sugar, also qualifies.2Centers for Medicare & Medicaid Services. Glucose Monitor – Policy Article
Once approved, Medicare pays 80% of the approved amount after the 2026 Part B deductible of $283, and you owe the remaining 20%.3Centers for Medicare & Medicaid Services. 2026 Medicare Parts A and B Premiums and Deductibles4Centers for Medicare & Medicaid Services. Medicare Coverage of Diabetes Supplies A Medigap policy may cover that 20%. Your initial visit to establish eligibility can be in person or via telehealth, but the doctor must document your diabetes diagnosis, confirm you’ve been trained on the device, and verify the CGM is prescribed according to FDA-approved uses.2Centers for Medicare & Medicaid Services. Glucose Monitor – Policy Article
Get the Documentation Right
Your doctor’s office handles most of this, but knowing what’s required helps you catch gaps before they cause a denial. A complete documentation package typically includes:
- Recent fingerstick blood sugar logs showing patterns of high or low readings
- A1C lab results from the past two to three months
- Records of your current insulin regimen, including dosages and frequency
- History of severe low blood sugar episodes, emergency room visits, or hospitalizations related to glucose management
Most insurers also require a letter of medical necessity from your prescribing doctor. The letter should explain why a CGM is needed for your specific situation and reference the insurer’s own clinical policy criteria. A generic letter that reads like a form template carries less weight than one detailing your particular history: how many times you’ve been hospitalized, what management methods you’ve tried, why they fell short.
Many insurers have their own CGM request forms that your doctor’s office must complete. These often require signatures from both the physician and you. Missing a signature or leaving a field blank is one of the most common reasons for delays. Keep copies of everything you submit. When paperwork goes missing, and it does, you’ll be able to resend immediately rather than starting over.
Get Prior Authorization Before the Device Ships
Many plans require prior authorization before they’ll cover a CGM. Skipping this step, or not realizing it’s required, can leave you holding the full bill even when the device would otherwise be covered.
Your doctor’s office submits the request using forms available on the insurer’s website or provider portal. Standard processing usually takes one to two weeks. Expedited reviews, available for urgent medical need, are typically decided within a couple of business days. If the insurer asks for more information, respond quickly. Letting the request sit can force the whole process to restart.
Once approved, the authorization is usually valid for six to 12 months. Mark the expiration date on your calendar so you can begin renewal before coverage lapses.
Make Sure the Claim Is Filed Correctly
How the claim gets filed depends on the benefit category. For DME billing, the medical supply company usually files directly with your insurer. When the CGM runs through pharmacy benefits, the cost is handled at the pharmacy counter and you pay your copay or coinsurance at the point of sale.
If you’re filing yourself or want to verify what your provider submitted, the billing codes are worth knowing. For therapeutic CGMs covered under Medicare, the codes changed in 2023 to E2103 for the receiver or monitor and A4239 for the supply allowance.5Centers for Medicare & Medicaid Services. LCD – Glucose Monitors (L33822) For non-therapeutic CGMs, the HCPCS codes are A9276, A9277, and A9278.6TRICARE Manuals. TRICARE Policy Manual – Continuous Glucose Monitoring System Devices Providers may also bill CPT 95250 for sensor placement and training and 95251 for interpreting the data.
A manually submitted claim should include an itemized receipt, the provider’s National Provider Identifier number, and the insurer’s claim form. File as soon as possible after purchase. Deadlines are commonly 90 days from the date of service, though some plans allow up to a year.7National Association of Insurance Commissioners. Health Care Bills – Filing Health Insurance Claims Your plan documents will list the exact deadline.8U.S. Department of Labor. Filing a Claim for Your Health Benefits
Appeal a Denial
Denials happen even when you’ve done everything right. Common reasons include insufficient medical necessity, a coding error, or a documentation gap. The denial letter will explain the specific reason and outline your appeal rights, including deadlines and where to submit your response.
You generally have 180 days from the date you receive a denial to file an internal appeal.9eCFR. 29 CFR 2560.503-1 – Claims Procedure A strong appeal packages together everything the initial submission lacked. If the denial cited insufficient medical necessity, a revised letter from your doctor that directly addresses the insurer’s criteria and includes updated glucose data can change the outcome. If the denial was a coding error or missing paperwork, resubmitting the corrected claim with an appeal letter is usually enough.
When internal appeals fail, you can request an independent external review. File within four months of receiving the final internal denial.10HealthCare.gov. External Review An outside reviewer examines your case, and the decision is binding on the insurer.11eCFR. 45 CFR 147.136 – Internal Claims and Appeals and External Review Processes Your state’s department of insurance or consumer assistance program can help you navigate the process. Keep copies of every letter, form, and phone call log.
Lower What You Still Owe
Even with insurance, out-of-pocket costs add up, especially before you meet your deductible. The IRS treats blood sugar monitoring equipment, including CGMs, as a qualified medical expense, so paying for sensors, transmitters, and receivers through a health savings account or flexible spending account uses pretax dollars.12Internal Revenue Service. Publication 502 (2025) – Medical and Dental Expenses
CGM manufacturers also run assistance programs. Abbott offers reduced pricing on Libre sensors for commercially insured patients, plus a free starter sensor and reader through its MyFreeStyle program. Dexcom has a patient assistance program for people with Type 1 diabetes who earn below 400% of the federal poverty level and aren’t on a government plan. Medtronic offers reduced-cost sensors and transmitters for people without insurance coverage, and up to three months of free sensors for those who recently lost a job or insurance. Eligibility rules change, so check with the manufacturer directly.
Keep Coverage From Lapsing
Getting approved once doesn’t set you up forever. Most authorizations expire after six to 12 months, and insurers require evidence that the device is still medically necessary before they’ll renew. Letting it lapse means starting the approval process from scratch.
Medicare has a specific rule: your treating doctor must see you every six months, in person or via telehealth, and document that you’re still using the CGM as prescribed and following your treatment plan.13Centers for Medicare & Medicaid Services. Glucose Monitoring Supplies Miss that visit and your supplier can’t ship your next round of sensors.
Private insurers have their own renewal criteria, but the pattern is the same: ongoing documentation that the CGM is being used and is still clinically needed. Keep your glucose data organized, attend scheduled follow-ups, and start the reauthorization paperwork at least a month before the current authorization expires. The people who lose coverage aren’t usually the ones who fail to qualify. They’re the ones who miss a deadline.