Joslin Answers Your Questions

Joslin Diabetes Center experts answer commonly asked questions about diabetes monitoring, treatment, self-care, meal planning, and more.
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Topic: Blood Glucose
Question: My doctor told me about a new way to check glucose called continuous glucose monitoring. From what I understand, you have to wear some kind of equipment all the time, but no longer have to do fingersticks. That would be great. Is this true? How can I get a continuous glucose monitor?

Answer: Continuous glucose monitoring, or CGM, is a new technology that allows you to receive glucose readings every few minutes, 24 hours a day. CGM devices consist of three parts:
  1. A sensor that is inserted right underneath the skin
  2. A transmitter that relays glucose readings from the sensor to a receiver
  3. A receiver that allows you to view your glucose readings
Unlike glucose meters, which measure the amount of glucose in your blood, CGM devices measure glucose from your interstitial fluid-the fluid that sits between the cells in your body. CGM devices also alert you when your blood glucose is high or low, and they allow you to immediately see the effects of food, activity, and insulin on your glucose.

CGM is best suited for people with diabetes who are having difficulty controlling glucose levels, who have a condition called hypoglycemia unawareness (the inability to sense low blood glucose), or who perhaps need to make a change to their diabetes treatment plan, such as starting on insulin, for example.

It's important to note that, currently, you would still need to check your blood glucose with your regular blood glucose meter even if you wear a CGM device. That's because all treatment decisions are based on fingerstick readings rather than sensor readings. At this time, three companies make CGM devices. They all require a prescription from your healthcare provider. Insurance coverage typically is limited for CGM; the devices cost between $800 and $1,300; and the sensors (which are disposable and last between three to seven days) cost about $35 to $65 each.

Wearing a CGM device is a lot of work: You must learn how to properly insert the sensor, use the device itself, calibrate the device, and have an understanding of what CGM can-and can not-do. However, the hard work can pay off. CGM has helped many people identify problem areas, such as high glucose levels after eating meals, and develop strategies to help address them.

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