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Glucose Monitoring

Dexcom G5

By in Glucose Monitoring

Dexcom G5

The Dexcom G5 CGM is still widely used because not all insurance plans cover the G6. (It is however, be retired in June 2020 along with the G4.)  It can be worn for up to 7 days, but this time period can be extended. The G5 requires calibrations using your blood glucose meter. The data from the Dexcom G5 can be sent to a reader or a compatible smartphone. If the person wearing the G5 is using a smartphone and Dexcom G5 App as the receiver, data can be shared with followers. Data cannot be shared from the receiver. You cannot take acetaminophen (Tylenol) when wearing the G5.


Calibrating the G5 is one of the most important things you will do to make sure glucose readings are accurate. It requires a start up calibration with two meter blood glucose readings, followed by calibrations every 12 hours.  Here are a few things to keep in mind when doing a calibration:

  • Only do calibrations when the trend arrows are steady.
  • Have clean hands when obtaining a blood glucose meter reading for calibration.
  • Enter the number into the CGM immediately.
  • Calibrate when the numbers on your CGM and meter are not more than 30% apart. Remember, the CGM measures interstitial fluids whereas the blood glucose meter measures the plasma blood glucose. The numbers will always be different on the two devices but you don’t want them to be widely different when calibrating.
  • Be cautious not to over-calibrate. A good rule of thumb is to calibrate 2-3 times a day.
  • Always calibrate before going to bed.

Inserting the Sensor

Some people who use the Dexcom G5 CGM find it harder to insert than other sensors. You can prepare by watching the official Dexcom G5 “Inserting Your Sensor” video. If you find sensor insertion stressful, ask a friend or family member for help. Parents of very young children might consider using a numbing cream, like EMLA, if their child finds sensor insertion painful.


Reviewed by Laura Jacobsen, MD on 2/12/20.

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.