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Glucose Monitoring

Interpreting CGM Data

By in Glucose Monitoring

CGM data are very powerful in helping you keep your diabetes on track, but the data can be overwhelming. Where to start?

We recommend looking at the data every week. Start with the big picture:

  • What is your time in range between 70-180mg/dL?
  • What is your average sensor glucose level over the past two weeks?

Next, check for lows:

  • You should have less than 1% of values below 54 mg/dL
  • You should have less than 4% of values below 70 mg/dL

If you notice you are having more lows in either of the above categories, talk to your diabetes care team about reducing your risks, especially if you are having severe lows or lows overnight.

You could also look for trends in the following areas:

  • Are blood glucose values stable overnight?
  • Are there certain times during the day with lots of lows or highs? (For example, every day after lunch?)
  • How is blood glucose affected by exercise? You should look at glucose values during intense exercise, two hours after exercise, or overnight. How do different types of exercise affect glucose levels? Are you high during weightlifting but low when you swim?
  • How is glucose affected by the timing of your mealtime insulin doses?

Share your insights with your diabetes care team so you can work in partnership to make changes to your diabetes management plan.


Reviewed by Anastasia Albanese O’Neill, PhD, 7/15/19

This document is not intended to take the place of the care and attention of your personal physician or other professional medical services. Our aim is to promote active participation in your care and treatment by providing information and education. Questions about individual health concerns or specific treatment options should be discussed with your physician.