CGM readers

If you're looking for a complete replacement to finger prick testing....it doesn't exist yet.

If you're looking for technology that significantly cuts down on finger prick testing and provides invaluable information DIFFERENT from an individual bg test, that's where a Dexcom CGM would likely fit the bill.

A CGM serves a specific purpose: to spot trends in your blood sugar levels throughout the day. While the individual readings are becoming much more accurate, a CGM is not a replacement technology but rather supplemental technology.

To explain that: a basic glucometer is what I trust for specific readings at a single point in time. My CGM tells me what my blood sugar is doing in between those readings.

The libre and the dexcom measure glucose in interstitial fluid, rather than blood - interstitial fluid is about 15 - 20 minutes behind your blood. So your blood test and your CGM are measuring different things.

The advice that comes with the dexcom is that it is not supposed to be used for treatment decisions - you aren't supposed to look at your dexcom and use the number on there to decide how much insulin to give. It does require calibration twice a day.

It has a two hour period after you put the sensor in for it to settle in to your skin, to be honest if you can afford it it could probably do with a 2 day period, I find it is a bit less accurate for the first couple of days while it settles in. It loses accuracy at the extremes (if you are very high or very low) but the same can be said of a blood glucose monitor.

You can't take paracetamol when using a dexcom because thatmdoes something to your interstitial fluid and screws the accuracy of the sensor.

So long as you are aware of the limitations (and I think they are very small limitations in the grand scheme of things) the dexcom is brilliant and it scores very well for accuracy (better than the enlite, but I have a feeling that the libre is better than both for accuracy). I'm confident that my dexcom is very accurate and I'm very happy with it.

Both Libre and the European version of the Dexcom G4 have similar "accuracy" levels. The Dexcom G5 is substantially better.

As the others have said, it's not testing blood so you shouldn't expect the same results.

I used the Libre for 18 months and found it to be brilliant.