Remarkable performance of two Libre CGMs. If money is no object and if you want to be absolutely sure the CGM is working correctly, try wearing two Libre CGMs. The Contour Next One’s accuracy could be transferred to this two-CGM system.
I don't work for Abbott. Doing this experiment just for fun.
In a previous experiment, I demonstrated that two Libre CGMs, one on the left and the other on the right chest, tracked each other, but they have an offset. Such tracking suggests that they are tracking the interstitial glucose, and this fact can be used to prove that the CGMs are working correctly. The change in the offset between the two CGM trajectories can be used to tell if a new calibration is needed, thus assuring the calibration is always up-to-date.
On one hand, u/Equalizer6338 suggested that I repeat the experiment to show that the results are reproducible. On the other hand, u/jon20001 suggested that two CGMs on different parts of the body may respond differently. So, I thought, for this new experiment, why not put the two CGMs on one side of the chest and let them be as close as possible (~2.5 inches c to c between them)?
And voila! My jaw nearly dropped. After 30 hours, the glucose trajectories of the two Libre CGMs are nearly on top of each other, and I have never seen this behavior before. However, for the initial 30 hours or so, the tracking was not as good. I think that it might be due to the body’s reaction to the filament insertion. In anticipation, I did presoak the two CGMs for 24 hours, but it didn't help.
These results suggest that the drifts of the two Libre CGMs, from two different lots, are negligible and that the calibration functions also are working flawlessly. The results also suggest good manufacturing control. My hats off to the researchers at Abbott and my admiration of their excellent design and excellent work.
Posted Feb 23, 2026, 6:00 AM UTC