Dexcom G7 - Introduction

Dexcom G7 - Introduction

This page is not giving you medical advice or treatment advice, and that is very much on purpose! I am not a medical professional, and even if I were, I don’t know your personal circumstances. If you need medical advice, consult your physician! If, at any time, you have reason to doubt your G7 readings, use one or more finger-stick measurements to confirm your G7 readings. Base your treatment decisions (bolus, etc.) on the finger stick reading, and in accordance with your physician’s instructions.

For users with an insulin pump controlled by the G7: Until you have reached a full understanding of your G7’s behavior and when, in your particular case, its readings can be trusted, you may need to double-check, as frequently as necessary to give you confidence, with finger stick readings. Read the page on reading comparisons for important information on interpreting the differences.

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Dexcom G7 - Introduction

As a user, I will categorically state that Dexcom and its G7 product are far from “great” products. When the device works as advertised, it is a great help in diabetes management, particularly when used with pumps, for those who use them. That said, the overall user experience seems lackluster. The information in these pages is not intended to be an apologist for Dexcom, but rather to help people have a better experience (where possible) and to let them complain more effectively when appropriate.

Over the past year or two, I have found myself responding to posts on Facebook forums (there are many on the topic of Dexcom) and Reddit. Some of these responses focused on personal experiences, but not infrequently, I found myself educating people on the issues at hand. Sometimes people have unnecessary anxiety about readings, sometimes they want to rip out and replace a sensor before they should, etc.

One of the most frequent issues I see people complaining about is a (large) discrepancy between the G7 reading and a finger stick reading. Contrary to what many have read or come to understand, this is not a simple matter of looking at the difference and passing a straight-up judgment. There is a page dedicated to understanding this topic, but in summary, with results taken when blood glucose levels are stable (only!), a difference of up to 22.5% may occur in up to 75% of cases, though occasionally it can be almost 50%. This percent difference is about 22 mg/dL for true glucose levels around 100 mg/dL, but can be as large as 44, resp. 56 mg/dL at true levels of 200, respectively 250! If you compare when your levels are (rapidly) increasing or decreasing, you may see much larger differences, and neither G7 nor finger stick may be performing outside expectations!

Many, but perhaps not all, issues are described on the Known Issues page. Sometimes the goal is to correct expectations, sometimes to improve the user experience, and to make it clear when, and when not (yet) to replace a sensor. When all else fails, I explain how to contact Dexcom for help or to request a replacement.

Please use the links to the various pages shown above for further reading. If you are new to this, I suggest reading them in order.

A note about type I vs. type II users: I am a type II user, and consequently, my personal experience (where I mention it) is more likely to be correct for only type II users. Based on a lot of feedback from both types of users, I have come to the conclusion (no evidence) that the physiology of the two types is sufficiently different that G7 behavior, accuracy, and calibration ability can be quite different.