A continuous glucose monitor (CGM) monitors blood sugar (glucose) levels. A CGM can help people with diabetes manage their blood sugar levels. Most people who use a CGM have type 1 diabetes.

People with type 2 diabetes are unable to regulate the hormone insulin properly. This makes it difficult to control blood sugar levels, which can lead to serious health problems if left untreated.

Type 2 diabetes is the most common type of diabetes, affecting around 90-95% of people with diabetes. While a person usually receives a diagnosis in adulthood, an increasing number of children and young adults have a type 2 diabetes diagnosis. A CGM may help keep the condition under control, but there is currently limited evidence to confirm this.

Read on to learn more about CGMs, the importance of tracking glucose levels, who should not use this device, and when to contact a doctor.

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A CGM is a small device that takes blood sugar measurements every few minutes. The device has a sensor that goes under a person’s skin.

The advantages of a CGM include the following:

  • It allows a person to see trends in their glucose levels over time.
  • It enables a person to access their blood glucose information instantly.
  • It alerts people if their blood glucose levels are too high or too low.

A person normally wears their CGM on their belly or arm. It has a tiny sensor that goes under the skin.

Every few minutes, the sensor measures the amount of glucose the person has in the fluid between their cells, known as their interstitial glucose level.

The CGM also has a wireless transmitter that sends the glucose data to a monitor. The monitor might be a separate device or on an insulin pump, or a person might carry it in their pocket or purse. Some devices can send the data directly to an app.

Regular blood sugar monitoring is essential for managing type 2 diabetes. It allows a person to see what foods, medicines, or activities increase or decrease their blood glucose levels.

They can use this data to work with their doctor to formulate a diabetes care plan for their needs. Managing blood sugar levels can also help to delay or prevent complications of diabetes, including:

Although continuous glucose monitoring may benefit patients with type 1 diabetes, there more research needs to determine whether it offers similar benefits in people with type 2 diabetes, even if they are taking insulin.

Only adults and children with a doctor’s prescription can get a CGM. Children under 2 years old may not be able to have a CGM.

A doctor may prescribe a CGM for a person who:

  • is on intensive insulin therapy, known as tight blood sugar control
  • cannot tell when their blood glucose decreases and cannot tell when they need to treat it, known as hypoglycemia unawareness.
  • often has high or low blood glucose

Some people may only need to wear a CGM for a few days to help them adjust to a new diabetes care plan.

While a CGM can help monitor blood glucose levels in people with type 2 diabetes, it does not replace seeing a doctor.

If a person’s blood sugar is too high or too low for too long, it can lead to serious health problems, including heart disease, loss of vision, kidney disease, seizures, and even death.

A person should contact a healthcare professional if they have any questions about the safe use of their CGM or if they are worried about their symptoms.

Common symptoms of low blood sugar include:

Common symptoms of high blood sugar include:

  • extreme tiredness
  • thirst
  • blurred vision
  • more frequent urination

Below are some common questions and answers on this topic:

Do I stop using the fingerstick checks to monitor glucose levels?

No. To ensure a CGM gives accurate readings, a person needs to test daily using a blood sugar meter. This involves testing a small amount of blood by pricking the end of a finger.

How much does CGM for type 2 diabetes cost?

There are various costs associated with using a CGM for type 2 diabetes. According to one source, these costs total 2,500–$6,000 annually. They include a flash reading device with a one-off fee, plus replaceable sensors that can cost anywhere from 120–$200 a month.

Other devices cost 1,000–$1,400, with replaceable sensors costing 35–$100 every 7–10 days. Additionally, replacement batteries can cost around $500 a year.

Does insurance cover the costs?

A person receiving insulin through a pump or multiple daily injections and requiring at least four fingerstick glucose tests daily can get a CGM using Medicare. If a person’s insurance company covers the cost, they may need to see specific documentation, including a letter stating that the CGM is medically necessary.

People with type 2 diabetes have difficulty controlling their blood sugar. Blood glucose monitoring is important in helping a person understand what foods and medicines raise or lower their blood sugar.

The advantages of a CGM include instant access to blood glucose information and the ability to chart levels over time.

However, using a CGM does not replace visiting a doctor.