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A continuous glucose monitor (CGM) is a monitoring device used by people with diabetes. They apply them directly to the skin and monitor blood sugar readings in real time.
Dexcom’s CGM and Abbott’s FreeStyle Libre are widely used brands of CGM systems. These two systems have many similarities. Both are used as an alternative to blood sugar tests and provide real-time data for diabetics.
Key differences between Dexcom and FreeStyle Libre include sensor characteristics, reading frequency, minimum usage period, and alert and alarm types.
This article explains what CGM is, highlights the similarities and differences between Dexcom and FreeStyle Libre (including accuracy), and provides an overview of CGM insurance coverage.
A CGM is a wearable device that is placed on the skin and provides continuous, real-time access to blood glucose readings.
These devices provide complete access to blood glucose data that cannot be obtained using traditional glucose meters alone. CGM data has proven to be more effective than hemoglobin A1C testing in assessing the success of diabetes treatment.
CGM data also helps healthcare providers personalize treatment plans for patients. It is usually recommended for use by people who require insulin to manage diabetes.
CGMs do not require multiple finger pricks, making them an attractive option for people who need to frequently monitor their blood sugar levels.
Other benefits of using CGM include:
- ease of use
- Ability to easily track blood sugar trends
- Ability to detect readings that are too high or too low
- Ability to reduce the effects of long-term complications associated with measurement fluctuations
Still, you should have access to blood glucose monitoring in cases where your CGM reading may be inaccurate, such as when your device issues an alert or switches your insulin dose. You may need to compare the CGM results with a finger prick test or blood glucose meter.
Types of CGMs are classified based on how they store and display blood glucose information.
There are three types of CGM.
- Real-time CGM that automatically displays data
- Intermittent scanning CGM that requires frequent scanning of the CGM to display and save data
- Professional or provider-directed CGM used for a short period of time.Provider must download and verify data
Healthcare provider and individual preferences, lifestyle factors, and insurance coverage can influence the selection of these CGM systems for effective diabetes management.
A CGM consists of a sensor, transmitter, and receiver.
The sensor is inserted under the skin, usually on the abdomen or arm, and secured with adhesive. The sensor measures glucose levels in the fluid surrounding the body’s cells.
The glucose level in this fluid is very similar to the glucose level in the blood. The sensor is for temporary use and must be replaced according to the instructions.
The sensor is connected to a transmitter, which wirelessly sends data to a receiver or compatible smart device.
This means that in most cases you won’t need to prick your finger as often. However, some of his CGM models require a finger stick with a glucose meter to ensure data accuracy.
The receiver then collects data from the sensor and displays it in real time, allowing for continuous glucose monitoring.
CGM is durable and can be worn all day. There’s no need to remove it while exercising, showering, or sleeping.
Examples of CGMs available include Dexcom and FreeStyle Libre, two commonly used CGM systems.
Dexcom’s CGM system includes a sensor for placement on the back of the arm or lower abdomen. It also includes the option of placing the sensor on the upper buttocks when used on children.
The sensor can be used for up to 10 days and requires no calibration. Both systems have smartphone capabilities and applications for data monitoring and sharing.
Available Dexcom CGM products include:
- Dexcom G6 (adults and children 2 years and older)
- Dexcom G7 (adults and children 2 years and older)
Dexcom CGM products require a prescription.
Abbott’s FreeStyle Libre CGM system includes a sensor for placement on the back of the upper arm.
The sensor can be used for up to 14 days and requires no calibration. Like Dexcom, each system features smartphone functionality and data monitoring and sharing applications.
FreeStyle Libre CGM products available include:
- FreeStyle Libre 14 Day (Adults 18+)
- FreeStyle Libre 2 (adults and children 4 years and older)
- FreeStyle Libre 3 (adults and children 4 years and older)
Like Dexcom’s CGMs, these require a prescription from your healthcare provider.
Those who benefit most from CGM include those who have difficulty controlling their blood sugar, those on intensive insulin therapy, and those who are unaware of their hypoglycemia.
In general, GCM systems operate similarly and both systems provide valuable data. However, there are some important differences between Dexcom and FreeStyle Libre.
The Dexcom system is a real-time CGM that continuously tracks blood sugar levels throughout the day and captures data every 5 minutes. Glucose readings are updated automatically.
The Libre system automatically reports measurements up to every minute, except for FreeStyle Libre 14 days. FreeStyle Libre 2 requires scanning the sensor to update the readings.
Dexcom sensors last up to 10 days, while FreeStyle Libre sensors last up to 14 days.
Both Dexcom systems can be programmed to work with insulin pumps, but only the FreeStyle Libre 2 system is compatible with insulin pumps.
Dexcom is safe for children as young as 2 years old, but the minimum age for using FreeStyle Libre is 4 years old.
The U.S. Food and Drug Administration (FDA) has approved Dexcom G7 and FreeStyle Libres 2 and 3 for use during pregnancy.
Both Dexcom and Libre can provide reliable and accurate continuous blood sugar monitoring. Factors such as proper use and calibration of the sensor, proper insertion technique, and sensor location can affect accuracy.
A recent clinical trial evaluated the accuracy of each of the Dexcom and FreeStyle Libre CGM systems. Researchers compared CGM measurements to blood sugar levels.
Although both devices had high accuracy, our research revealed that the FreeStyle Libre 3 was more accurate than the Dexcom G7.
When deciding which CGM is right for you, you and your provider may consider factors such as your personal preferences, specific health needs, and cost. Research your options and discuss them with your diabetes care provider.
CGM data must be monitored under the supervision of a healthcare provider.
Insurance coverage for CGM systems depends on factors such as:
- Type of insurance (e.g., private or government-provided)
- Insurance company
- Compensation conditions and details
- personal medical needs
Many insurance plans offer coverage for CGM devices for people who require intensive insulin therapy, which typically involves multiple daily doses of insulin.
Coverage may vary depending on certain criteria, such as documented uncontrolled diabetes, perceived hypoglycemia, or frequent blood sugar fluctuations. Some plans may or may not cover specific CGM brands or models.
Some insurance plans may require CGM prescriptions to be filled through a durable medical equipment (DME) distributor rather than a traditional pharmacy.
Check your insurance policy and familiarize yourself with what it covers. Talk to your diabetes care provider and work with your insurance representative to determine coverage options and the latest requirements for his CGM device.
The number of diabetics using CGM continues to grow. CGM has evolved as a less invasive method to optimize glycemic control and provide real-time data while minimizing the need for traditional blood glucose monitoring.
Dexcom and FreeStyle Libre CGMs are widely used and popular due to their convenience, simplicity, and ease of use. Taking CGM readings is also less painful than using traditional blood glucose monitors.
Both adults and children can use Dexcom and Freestyle Libre with a valid prescription. Key differences between Dexcom and FreeStyle Libre include how often data is uploaded, how long the sensor lasts, and who can safely use it.