Continuous Glucose Monitoring: What You Need to Know

Medically Reviewed By Jenneh Rishe, RN
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Continuous glucose monitoring helps you manage type 1 or type 2 diabetes through wearable technology that monitors your blood sugar 24 hours a day.  If you have diabetes, you may need to closely monitor your blood sugar. Diabetes occurs when the body cannot produce or use insulin efficiently. Insulin is a hormone that helps your body use blood glucose for energy.

More people are turning to this technology as they see the benefit of closely tracking their blood sugar throughout the day. Keeping your blood sugar levels in a healthy range will help you feel better and prevent complications.  

This article will discuss continuous glucose monitoring and who benefits from using it. It also explains how the monitor works and reviews the benefits and limits of the technology. 

What is continuous glucose monitoring?

A man checking his glucose levels with his phone
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Continuous glucose monitoring (CGM) uses technology to track blood sugar levels 24 hours a day. It is an efficient way to track how your glucose levels change throughout the day. It not only displays real-time levels but also keeps track of trends to help you make informed decisions about your diet, physical activity, and medications.

Who needs continuous glucose monitoring?

Typically, people with type 1 diabetes benefit from CGM. However, more people with type 2 diabetes are also turning to CGM. A 2021 randomized clinical trial found that CGM allowed people with type 2 diabetes to better monitor their glucose levels than more traditional blood glucose monitoring methods.

In 2018, the Food and Drug Administration (FDA) approved the first CGM device for adults and children as young as 2. 

Your doctor may recommend a continuous glucose monitor if you:

  • require tight blood sugar control
  • are unaware when your blood sugar is dropping
  • have frequent blood sugar level fluctuations

How does continuous glucose monitoring work?

CGM works through a tiny sensor inserted just under your skin, usually on your stomach or arm. This sensor measures your glucose every few minutes and wirelessly sends the information to either your smartphone or a separate device small enough to carry in your pocket or purse. 

The sensor is always on and recording; there is no interruption if you are showering, exercising, working, or sleeping. 

Many blood glucose monitors are programmed with special features, such as:

  • an alarm that sounds when your glucose level is too low or too high
  • the ability to download your glucose data to easily see your blood sugar trends
  • ability to track when you eat, work out, and take your medication and see how those activities affect your levels
  • ability to send data to another person’s phone, such as a caregiver, parent, or partner
  • 24-hour phone support

You may need to check your blood glucose level with a finger stick test to ensure your CGM is still measuring correctly. But having a CGM greatly reduces the number of finger sticks usually required for blood sugar monitoring. 

What are the benefits of continuous glucose monitoring?

Before the invention of CGM, people with diabetes relied on standard blood glucose monitoring by finger stick tests throughout the day. This constant pricking of the fingertips sometimes led to nerve problems or other issues. Another downside to standard monitoring is that checking blood sugar levels in public settings is not very convenient. 

When relying on standard testing, you get small snapshots of your blood sugar level throughout the day and you may not always know when your blood sugar is trending too high or too low. 

Compared to standard glucose monitors, using a CGM system helps you:

  • manage your blood sugar levels throughout the day, every day
  • have fewer high-glucose or low-glucose emergencies
  • need fewer finger sticks
  • provide better data for your doctors so they can give you more personal coaching

Looking at the graph on your device’s screen, you can see if your blood sugar is trending up or down and how quickly, so you can make decisions to keep your blood sugar in the target range. 

People with diabetes who learn to manage their blood sugar well tend to feel better and have fewer complications from the disease. The ability to continuously monitor your blood sugar levels and adjust your diet and lifestyle accordingly may help reduce the need for additional doctor visits or medication adjustments.

To get the best results, use your CGM device every day or nearly every day. 

What are the limits of continuous glucose monitoring?

Experts are still working to make CGMs more accurate and user-friendly. 

One downside of CGM is that finger sticks, while needed less often, are still necessary to check the accuracy of the CGM device. However, some newer models may not require this type of calibration.

One debatable downside is the cost. CGM monitors are more costly to purchase than a standard glucose meter. However, some insurance plans do cover them. When taking into account that standard glucose meters also require multiple lancets and finger tests throughout the day, the CGM may save you money in the long run.

Frequently asked questions

Here are a few other commonly asked questions about CGM. Jenneh Rishe, RN, has the answers.

Who qualifies for continuous glucose monitoring?

Adults and children who meet certain conditions can qualify for CGM with a doctor’s prescription. Doctors will typically recommend CGM for people who require intensive insulin therapy, cannot tell when their blood sugar levels change, or experience frequent fluctuations of blood sugar.

Is CGM more expensive than a standard glucose meter?

According to the National Institute of Diabetes and Digestive and Kidney Diseases, a CGM device will cost more than a standard glucose monitor. However, some insurance plans may cover part of the cost of CGM.


CGM devices help people with type 1 or type 2 diabetes easily monitor their blood sugar levels throughout the day. These devices use a small sensor under the skin to monitor your blood sugar every few minutes and send the information to your phone or another small device. 

The CGM device allows you to see daily blood sugar trends and will send an alert to tell you or a loved one when your blood glucose levels are trending too high or too low. 

This technology allows people with diabetes to make better blood sugar management and overall health decisions.

Talk with your doctor to determine if CGM is right for you.

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Medical Reviewer: Jenneh Rishe, RN
Last Review Date: 2022 Jul 28
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