A Continuous Glucose Monitor (CGM) is a medical device that provides continuous, real-time measurements of glucose levels throughout the day and night. This technology uses a small sensor, typically inserted just under the skin on the arm or abdomen, to measure glucose in the interstitial fluid. The sensor wirelessly transmits data to a dedicated receiver or a smartphone app, giving users and their care teams a dynamic picture of glucose trends without the need for constant finger sticks. Obtaining a CGM involves a structured process that begins with a medical order, navigates complex insurance rules, and requires establishing a reliable supply chain.
Determining Medical Necessity for a Prescription
Obtaining a CGM begins with a physician’s prescription, as the device is considered a regulated medical device. To qualify for subsequent insurance coverage, a patient must meet specific criteria for medical necessity, which are documented by the prescribing healthcare provider. The most common criterion is a diagnosis of Type 1 or Type 2 diabetes that requires the patient to be treated with insulin, including those who use multiple daily injections or an insulin pump.
Another requirement is a documented history of problematic hypoglycemia, referring to frequent episodes of low blood sugar that persist despite medication and diet adjustments. This includes a history of severe hypoglycemia or hypoglycemic unawareness, where the body does not show typical symptoms of low blood sugar. The prescribing physician must also ensure the patient (or a caregiver) is adequately trained on the device’s use and prepared to use the data for treatment decisions. This clinical documentation, detailing the diagnosis and treatment plan, is submitted alongside the prescription to the insurer to justify the medical need.
Navigating Insurance Coverage and Costs
After a prescription is secured, determining how your insurance plan will cover the device is the next step. Coverage largely depends on whether the CGM is classified under pharmacy benefits or Durable Medical Equipment (DME). Traditional Medicare, for instance, typically covers CGMs under its DME benefit (Medicare Part B), which applies to equipment used long-term in the home. Private insurance plans and Medicare Advantage plans, however, often cover the supplies through a pharmacy benefit, similar to how they cover prescription drugs. This distinction is significant because it dictates both the administrative process and the out-of-pocket costs.
If coverage falls under DME, the claim is processed through a specialized medical supplier, and the patient may be responsible for a coinsurance payment, often around 20% of the cost, after meeting their Part B deductible. When a CGM is covered under a pharmacy benefit, the cost is a copayment or coinsurance determined by the plan’s drug formulary. Many insurers also require a Prior Authorization (PA) before approving coverage, regardless of the benefit type.
The PA process can introduce delays in receiving the initial device while the insurer reviews the clinical records and determines approval. Patients without any insurance coverage should expect to pay the full retail price, which often runs hundreds of dollars per month for the continuous sensor supply. Carefully verifying the specific benefit pathway and any PA requirements with your insurance provider is a necessary step before placing the initial order.
Choosing the Right Supply Pathway
Once insurance coverage is confirmed, the patient must select the correct supply pathway for fulfillment, which can be one of three primary routes. The first option is a retail pharmacy, which is often the fastest method if the device is covered under your pharmacy benefit. Supplies can typically be picked up within one to two days, similar to other prescription medications. However, pharmacy staff may have limited expertise in CGM setup and support, and this pathway may sometimes be associated with higher copayments than the DME route.
The second common route is a specialized Durable Medical Equipment (DME) supplier, which is the required pathway for traditional Medicare coverage and many private plans. DME suppliers specialize in medical devices and often handle the complex Prior Authorization process directly with the prescribing physician. While the initial fulfillment may take longer due to administrative and shipping times, DME suppliers typically provide more comprehensive education and technical support for the device. Research suggests that patients who obtain their supplies through a DME channel may demonstrate better long-term adherence to their CGM therapy.
A third, less common pathway involves direct-to-patient programs offered by certain manufacturers, which can simplify the process but may not be compatible with all insurance plans. Selecting the wrong pathway, such as sending a DME-covered prescription to a retail pharmacy, can result in a denied claim and significant delays in receiving the device.
Managing Ongoing Sensor and Transmitter Refills
Continuous glucose monitoring requires a predictable and uninterrupted supply of components, including sensors and transmitters. The sensors, which are the disposable part of the system worn on the body, must be replaced regularly, typically every 10 to 15 days depending on the specific device model. The transmitter, which sends the glucose data from the sensor to the receiver, has a longer lifespan and usually needs replacement approximately every three months to one year.
Refills are generally managed on a 30-day or 90-day cycle, depending on the supplier and insurance rules. Patients must proactively track the expiration dates of their current supplies and place refill orders well in advance to prevent any gaps in monitoring. Many DME suppliers and pharmacies offer automated refill programs that help streamline this process and ensure a consistent supply arrives before the current batch runs out. Additionally, the original prescription must be renewed periodically, often annually, to maintain the supply chain and confirm continued medical necessity.