Dexcom g5 accuracy off!

I do trust my meter but not just any meter. I trust the Contour Next. I’ve got 3 models of it. My wife has two. We have several copies of some of the models. They all give similar, repeatable results under all bg levels that we ever encounter. I can’t say that,even remotely, for other meters that I’ve used (that includes many brands/models/model years going back to 1992)

Oh, I trust my meter, I was just saying that I don’t trust a single reading.
And now that I rarely test, for the last year or so, I will test at least twice any time I test, just to make sure I am doing my due diligence.
And anytime it varies more than a few points, I test more until I account for those numbers.

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A month or so ago, I had a reading that I suspected was wrong (because I wear a CGM and how I felt) so I retested. Glad I did, as it was reading way too high. Likely finger contamination.

It is best to calibrate when the arrow is straight. Never calibrate when the arrow is pointing up or down. I have found my Dexcom is very accurate when I calibrate during stable readings.


Calibrate about same two times of the day 12 hours apart daily
Only calibrate 2 times a day if possible - Anomalies do occur such as compression lows and other exceptions. Trying to catch those mess up the overall algorithm.
Calibrate as many hours as possible before or after a meal
Calibrate as many hours as possible before or after taking additional insulin due to high BG or cut back on insulin from low BG.

In other words calibrate twice a day, and only when BG is fairly stable. Not just a straight arrow, but a period when arrow has been straight for the longest period of time.

This is what I do with G5 and rarely is my fingerstick more than 10 points from my CGM. Due to low BMI I wear CGM between belly button and Xiphoid process and that eliminates compression lows and other issues while getting enough real estate for good interstitial fluid reading.

I recently switched from an Accu-Chek Aviva meter to the Contour meter provided by DexCom with my G5. I hadn’t used it before because it was consistently 20 points higher than the Aviva. But I finally ran out of Aviva strips and Medicare wouldn’t pay for any more.

What I found with the G5 was that if it was significantly off (meaning >20-30 points) from the G5, when I put the meter value into the G5 app on my phone, it just split the difference between the two. But if I put the meter value in twice (sort of like the first calibration for a new sensor), it displayed the meter value. So that’s the protocols l I use now.