Guardian Sensor

“Marinating” the Guardian 3 Sensor – Does it Work?

Some people using the Minimed 670G pump and Guardian sensor have recommended inserting a new sensor a couple hours beforehand prior to the expiry of their sensor they are using (a process they call “marinating” the sensor). In this way the sensor stabilizes well before you have to exchange it out with an old sensor.

I have tried this technique but with mixed results. It has worked beautifully lately but initially a couple sensors completely failed prior to the warm up period. As soon as I inserted the sensors into the transmitter, the green transmitter light did not blink as expected. Neither could the pump find the sensor. Maybe a bad batch?

Marinating helps the sensor signal stabilize quicker after the warm up period, although you still have to pay attention to upper thigh sites (they take longer to stabilize and can lead to major lows once the sensor stabilizes).

Auto Mode CGM Sensors

Upper Thigh Sensor Insertion Sites are More Accurate than Belly Sites

Bottom-line: For accuracy and fewer calibration errors I have found upper thigh sensor insertion sites better than belly sites. These sites take longer to stabilize (about 12-24 hours) but always give me very good accuracy and fewer calibration errors over the life of the sensor. Sensor values seem to match better with meter values for the upper thigh sites over the belly sites.

During my pump training, I was told that Medtronic now officially recognizes the outer side of the upper thigh as an FDA approved insertion site for the Guardian sensor. This was not the case for the Enlite sensor.

To shorten the time it will take the sensor to stabilize and enter Auto Mode, some people suggest inserting a new sensor and leave it in place a couple of hours prior to replacing the current sensor. I have had mixed results with this approach.