Medtronic CGM

Medtronic offers different CGM systems depending on the brand of the integrated insulin pump or stand alone CGM system.

  • Enlite Sensors and Transmitter for 630G. These sensors and transmitter cannot be used in 670G. 
  • Guardian Sensors and Guardian Link (3)Transmitter for the 670G insulin pump and stand alone Guardian system.

This information is intended to be used by an educator to review with patients in class or individually. Although effort is made to keep this information updated and accurate, the most reliable source of information regarding Medtronic sensors and insulin pumps is Medtronic, in collaboration with patients and their healthcare teams.

CGM Preparation for 670G

Medtronic 670Gpump transmitter 2019

  1. Charge Guardian Link (3) Transmitter. The transmitter from 630G WILL NOT work. Guardian Link (3) Transmitter can be verified by reading the back of the transmitter. See here.
  2. Complete Medtronic Learning Module for CGM
  3. Set up a Carelink account, upload pump settings and print off a report of pump settings. Carelink is essential to making use of CGM results. 
  4. Bring to the training session:
    • Pump
    • Glucose meter and strips
    • Guardian Link (3) Transmitter. 
    • Guardian sensors. Do not bring Enlite sensors that were used with the 630G. Enlite won’t click in. The box packaging appears the same for both Enlite and Guardian. Read the box to look for “Guardian”. 
    • Pump safety kit

Medtronic CGM Alerts and Alarms 630G and 670G (manual mode)

 Please note, the 670G in Auto Mode will not have all of the following alerts and alarms available. 

Setting Low Alerts

  • Low Limit: Used by pump features to set alerts. Can be individualized from 3.2 mmol/L to 5.0  mmol/L. Users can set up to eight time segments, each with a different low limit, each with the option to set Suspend on Low or not. Ask patient at what BG level they would consider taking action with glucose/carbohyrate to prevent a low, and set the “Low Alert” slightly above that. Individualize with patient. Keep in mind, if Suspend on Low is also set for that time segment, the pump will suspend insulin if the user does not respond to the alarm. 
  • Alert Before Low: Optional setting. When on, an alert is given when the sensor glucose is predicted to reach the low limit within 30 minutes.
  • Alert on Low: Optional setting. When on, an alert is given when the sensor reading reaches or falls below the low limit.
  • Low Snooze: Available after Low Settings are programmed. When on, a reminder alert is provided if the sensor reading is at or lower than Low Limit after the programmed snooze time (5 minutes up to 1 hour). Consider the typical time it will take to recover from a treated low, keeping in mind there may also be a lag between interstitial and blood glucose.
  • Suspend on Low: 
    • Optional. Insulin is suspended when sensor readings are at or below the low limit and the user has not responded to the alarm. 
    • Can be enabled for only specific individualized time segments eg. for overnight but not during the day, if desired.
    • When chosen, the Alert on Low is then automatically turned on. 
    • When a Suspend on Low alarm occurs, the user may clear the alarm if they are able to respond and treat their low. If a user does not clear a suspend on low alarm then insulin delivery will suspend for up to 2 hours unless the user manually resumes basal delivery. If the user does not respond to the alarm, the pump will automatically resume basal insulin after 2 hours.
    • Suspend on low is not to be used to prevent or treat low glucose as may result in prolonged hypoglycemia.

Setting High Alerts

  • High Limit: Used by pump features to set alerts. Can be individualized from 5.6 mmol/L to 22.2 mmol/L. Users can set up to eight time segments, each with a different high limit.
  • Alert Before High: Optional setting. When on, an alert is given any time the sensor glucose is predicted to reach the high limit
  • Time Before High: Optional setting and only available when using "Alert Before High". Can be individualized to alert from 5 to 30 minutes before high limit predicted to be reached.
  • Alert on High: Optional setting. When on, an alert is given when the sensor reading reaches or exceed the high limit.
  • High Snooze: Available after High Settings are programmed. When on, a reminder alert is provided if the sensor reading is at or over High Limit after the programmed snooze time (5 minutes up to 3 hours). Consider the typical time it will take to recover from a treated high, so not creating unnecessary alarms. Review insulin action time so patients don’t stack corrections
  • Rise Alert: Optional setting. When on, an alert is given when glucose is rising rapidly.
  • Rise Limit: Available if Rise Alert is on. User chooses one option.
    • One arrow up alerts users when rising at a rate of 0.056 mmol/L per minute or more (1.68 mmol/L in 30 minutes)
    • Two arrows up alerts users when rising at a rate of 0.111 mmol/L per minute or more.(3.33 mmol/L in 30 minutes)
    • Three arrows up alerts users when rising at a rate of 0.167 mmol/L per minute or more (5 mmol/L in 30 minutes)
    • A custom rise rate may be set

Medtronic CGM Tips

  • To limit overwhelm, consider adjusting, turning off or silencing some alarms especially if using AutoMode
  • Taping using 2 tapes is important to avoid early sensor failures
  • "Sensor updating" often means something is wrong
  • Suggest avoiding leaving calibration until the last minute in case the calibration is not accepted (the sensor will stop delivering values if a calibration is missed).
  • Suggest waiting longer than 15 minutes e.g. 1 hour, prior to recalibrating if calibration is not accepted. Recalibrating too soon after a "not accepted" result can lead to sensor failure.
  • Suggest patients aim to change sensor in mornings and/or on weekends where possible to avoid disruptions with sleep.