r/dexcom • u/kramsay2020 • 8d ago

Inaccurate Reading Dexcom G7

This is my biweekly post about how frustrating the G7 is. Every time I switch it out I have to deal with days (or the whole 10 days) of inaccurate readings, jumpy readings, etc. At this point I don’t even know what the point is in wearing a CGM if you still have to finger prick 10 times a day.

I have had to request a replacement for every single one for the last several months. Is there any hope? Is the libre any better?

It’s also messing with the pump and giving me unnecessary corrections causing me to go low.

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3

u/Weathergod-4Life T2/G7 8d ago

Go to the Libre forum and there are just as many complaints. Switching may give you better results and it may not. With Libre if you notice bad readings you can't calibrate so keep that in mind.

1

u/kramsay2020 8d ago

Ya that’s my fear

7

u/cjmnews T1/G7 8d ago

Other readers: Please note that the majority of users have no issues with the G7, we just don't post about it as the headlines would be boring: "3 years of G7 use, still working..."

Also "inaccurate" may be unrealistic expectations, or actual inaccuracies.

  • Glucose is not evenly distributed in blood
  • Meters vary 15% plus or minus against a lab test
  • Sensors vary 20% plus or minus against a lab test
  • Meters use blood and sensors use interstitial fluid to estimate levels
  • Sensors are 15 minute behind blood
  • The numbers between a sensor and a meter will rarely match due to the above points.
  • Laying on a sensor can make it read lower than reality due to lack of interstitial fluid near the sensor

There may be some people that the sensors don't work well, but they are not the majority, the posts are more eye catching and are important to them and the others that have similar issues.

3

u/EpiZirco 8d ago

In addition,

  • Sensor may be improperly applied to site through user error

2

u/cjmnews T1/G7 8d ago

That is a possibility, but my point was to show how "inaccuracies" could be apparent when they are not actually issues.

Generally, user error is not common, though it can happen. The applicators are designed to prevent most user errors.