Intro to Professional Continuous Glucose Monitors (CGM) 

The basics professional continuous glucose monitors

Content originally from the Professional Continuous Glucose Monitoring Implementation Playbook from ADCES and AphA. Updated by ADCES Subject Matter Expert Staff 2023.

Introduction to Continuous Glucose Monitoring (CGM)

Continuous glucose monitoring has become more widely adopted and utilized in recent years. Devices continue to improve in accuracy, reliability and convenience and insurance coverage is more widespread. Continuous glucose monitoring is considered a standard of care for people treated with intensive insulin programs.

Continuous glucose monitors measure interstitial fluid glucose levels and display numerical and graphic data regarding current glucose status, along with current and projected trends in the glucose. The projected future glucose trend is depicted by directional arrows. This allows users to proactively respond to glucose data rather than waiting for hyper or hypoglycemia to develop, therefore offering the ability to take preventive action to avoid hyper or hypoglycemia.

Personal CGM vs. Professional CGM

Continuous glucose monitoring devices are either owned by the user for personal use or provided by the health care center in the case of professional wear. Some personal continuous glucose devices link to other compatible devices, such as insulin pumps, blood glucose meters, smart phones, automated insulin-dosing systems and smart pens. Most CGM devices may be used as stand-alone devices. Some of the devices require periodic calibration with finger stick glucose checks.

Consumers who own personal CGM devices utilize the data in real time to make decisions about their diabetes management. The devices display trend arrows, indicating whether there is a pattern of rising or falling glucose to assist them in problem solving. Clinicians analyze retrospective data, sometimes combined with a user diary or log to gain insights into glycemic patterns. When personal CGM is unavailable for use, Pro CGM provides an option to see the impact of medication and lifestyle behaviors on glucose levels. 

Blinded vs. Unblinded Mode

Professional CGM can be performed in the “blinded” or “unblinded” mode. Unblinded CGM allows people with diabetes to see their glucose data and make treatment decisions about it in real time. Blinded CGM use allows for the capture of glucose data without influencing the individual’s behavior in the moment. Reviewing blinded CGM data with the person with diabetes can produce many “aha moments,” which allows for them to understand how their medications, diet and activity impact their glycemic control. The Dexcom G6 Pro allows for both blinded and unblinded mode. The Abbott Freestyle Libre Pro is available in the blinded mode. 


The Abbott Freestyle Libre Pro consists of a disposable combined wired glucose sensor/transmitter and a separate touchscreen reader device. The reader for Libre Pro is only used to activate the sensor, but it does not go home with the individual. When the sensor is returned, the clinic uses the reader to upload data from the sensor. The Dexcom G6 Pro CGM consists of three components: a disposable wired sensor which is inserted in the subcutaneous tissue via an applicator, a disposable data transmitter which is attached to the sensor after insertion, and a reader that verifies session start and allows subsequent data upload to CLARITY by the health care professional. For use in the unblinded mode, real-time glucose data can be viewed by the person with diabetes on a compatible smartphone using the Dexcom G6 app.

For more information, visit Find & Compare CGMs

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This site and its services do not constitute the practice of medical advice, diagnosis or treatment. Always talk to your diabetes care and education specialist or health care provider for diagnosis and treatment, including your specific medical needs. If you have or suspect that you have a medical problem or condition, please contact a qualified health care professional immediately. To find a diabetes care and education specialist near you, visit the ADCES finder tool.

ADCES and danatech curate product specifics and periodically review them for accuracy and relevance. As a result, the information may or may not be the most recent. We recommend visiting the manufacturer's website for the latest details if you have any questions.

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