What Is CGM?

A continuous glucose monitor (CGM) is a glucose monitoring system that features a wearable sensor that is inserted under the skin and a handheld device that allows patients to consistently track glucose levels with reduced fingersticks.2

What Is CGM?

For decades, doctors relied on blood glucose monitoring (BGM), despite several drawbacks:

  • Fingersticks can be painful, especially if you test multiple times per day.3
  • BGM can be inconvenient as comfortable testing space may be limited.3
  • A single BGM glucose number reads levels at one moment in time, and may miss fluctuations between tests.4

By comparison, CGM measures glucose levels in real-time. It can help you:

  • Monitor glucose levels with reduced fingersticks.2
  • Potentially reduce risk of hypoglycemia or hyperglycemia.1
  • Access data beyond basic readings to provide a more robust look at glucose trends.1
Importantly, frequent glucose monitoring with CGM is strongly
associated with better diabetes management and outcomes.6,7

CGM Made Easy

Apply sensor

Transmit sensor data

View Glucose Readings

Here’s What You Need To Know


A CGM uses a tiny sensor that is inserted under the skin to measure glucose levels via interstitial fluid, then transmits the information to a reader that displays your glucose value.5

The sensor measures glucose regularly, and you can view your level anytime via a monitor.5 The monitor may be part of an insulin pump or a separate device that you carry in your pocket or a purse. Some CGMs allow access to glucose levels on a compatible device such as a smartphone.5

Many CGMs may include features that work with information from your glucose readings, such as:

  • Alerts or alarms that notify you when your glucose level is too low or too high.
  • The ability to track your meals, physical activity and medicines.

You can download this data to a computer or smart device to more easily see your glucose trends. Some CGM models can even send real-time information to a parent, partner or caregiver’s smartphone.5

What are the differences between interstitial fluid (ISF) and blood glucose (BG) readings?

CGM SENSORS measure glucose from the interstitial fluid (ISF), a thin layer of fluid that surrounds the body’s tissue cells below your skin, and blood glucose measurements are taken directly from the blood.

Glucose enters the blood first and then minutes later moves into the ISF. This is why sensor glucose and blood glucose readings may be different (especially after eating, taking insulin or exercising).8

Are there special requirements to use a CGM?

Yes, there can be depending on the manufacturer and model. Speak with your doctor to learn more about the requirements specific to each CGM model.

Who can use a CGM?

People with type 1 and type 2 diabetes may qualify for CGM. For more information refer to the Get Access to CGM page.

What are the benefits of a CGM?

Compared to a standard blood glucose meter, using a CGM allows you the freedom to worry less about your disease and spend more time focusing on living your life. Benefits include:

  • Trends and patterns are shown on the device, which can help inform decisions on medication, activity and nutrition.5
  • It notifies you when your glucose levels are too low or high and some models can send real-time information to a family member or caregiver.5
  • It goes beyond current readings with additional insights based on where your glucose has been, and where your glucose is going.5
  • Monitor your glucose levels with reduced fingersticks.2

Does CGM eliminate finger sticks completely?

While CGM does not eliminate finger sticks completely, it does reduce their need.2 The U.S. Food and Drug Administration (FDA) has approved multiple CGM devices to replace fingerstick testing. Please speak with your health care provider and check manufacturing device recommendations to learn when a fingerstick test may be required.

Is CGM safe? How effective is it?

CGMs approved for use by the FDA to replace fingerstick testing have been proven as safe and effective. Research shows that a higher frequency of glucose monitoring is strongly associated with better diabetes management and outcomes.7

1 Rodbard, David. “Continuous Glucose Monitoring: A Review of Recent Studies Demonstrating Improved Glycemic Outcomes.” Diabetes technology & therapeutics vol. 19,S3 (2017): S25-S37. doi:10.1089/dia.2017.0035
2 Forlenza, Gregory P et al. “Practical Considerations on the Use of Continuous Glucose Monitoring in Pediatrics and Older Adults and Nonadjunctive Use.” Diabetes technology & therapeutics vol. 19,S3 (2017): S13-S20. doi:10.1089/dia.2017.0034
3 Grady, Mike et al. “A clinical evaluation of routine blood sampling practices in patients with diabetes: impact on fingerstick blood volume and pain.” Journal of diabetes science and technology vol. 8,4 (2014): 691-8. doi:10.1177/1932296814533172
4 Patton, Susana R, and Mark A Clements. “Continuous Glucose Monitoring Versus Self-monitoring of Blood Glucose in Children with Type 1 Diabetes- Are there Pros and Cons for Both?.” US endocrinology vol. 8,1 (2012): 27-29.
5 Monitoring Technologies – Continuous Glucose Monitoring, Mobile Technology, Biomarkers Of Glycemic Control Kathleen Dungan – < a href="" target="_blank">
6 Dunn, Timothy., et al. (2017). Evidence of a Strong Association Between Frequency of Flash Glucose Monitoring and Glucose Control Measures During Real-World Usage. E-poster presentation, The 10th International Conference on Advanced Technologies & Treatments for Diabetes (ATTD 2017) Paris, France, 15-18 February 2017.
7 Aijan, R., Insights from Real World Use of Flash Continuous Glucose Monitoring (2018, June). Symposium conducted at the conference for American Diabetes Association 78th Scientific Sessions, Orlando, FL., USA.
8 Basu, Ananda et al. “Time lag of glucose from intravascular to interstitial compartment in humans.” Diabetes vol. 62,12 (2013): 4083-7. doi:10.2337/db13-1132