CGMs, Help! compare

I’ve been on the Libre now for about 40 days, ending up my fourth sensor shortly. I will be applying for Medicare coverage, but my doctor says I need two months of fingerstick data. And that needs to show I test at least four times a day and that I make insulin decisions based on these readings. I’m collecting that data now and hope to make a request soon. I’m not surprised that PWD aren’t reporting success yet with the Libre and Medicare. The Libre was late to the game compared with Dexcom. And look how long it took to get Medicare coverage with that.

For those concerned about the 12 hour warm-up with the Libre, consider the solution suggested by the folks over at Make a one-time purchase of an extra reader. That way, you can start a second sensor while the first one is in its last 12 hours. When I apply for Medicare, I certainly plan to ask for a reader, even though I have the one I purchased myself.


Type 1 for 52 years. I do bg tests 5 times a day but wear the Medtronic Guardian 3. For me a CGM is a necessity. I glance at my CGM 20 - 30 times a day even though it’s a closed loop system because I want to know where my bg is now and where it’s headed. Medtronic CGM isn’t yet covered by Medicare but hopefully it will be. If you’re on insulin - it would be so very worthwhile to go with a CGM instead of a flash glucose meter. Lows at night are scary.

One way around the 12 hour warm up leaving you without the ability to use Libre to get your readings is to use a second reader, but you would lose having all your info tied to one reader. If you have two readers, you could put on a second sensor 12 hours before your current one ends, scan it with the second reader, then when the current one ends, that one will be ready. However, you can only read them with the reader that activates it, so, all your data would be split on 2 readers. If you don’t care about comparing all your data using one meter, this should work well.

Another way is there is some android app out there, not sure but it might be called Glimp, that will let you get readings after an hour. However, I believe this is the one that makes it so you cannot use your reader since it is used to activate your sensor, it is the only thing that can get your reading. If you don’t mind always using your phone instead of the reader, that might be a good one to use. One word of caution about the apps for these, some have been known to break the sensor. I am not saying it is this one, I truly do not remember which one people were complaining did that.

@Stang777 - I also recall some posting about Glimp doing exactly what you said. Being able to obtain readings during periods when otherwise you would not as well as at least one posting about Glimp breaking a sensor. We don’t use the Freestyle Libre (nor the Glimp) so have no experience but certainly recall the postings as you have mentioned them.

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Not going into the insurance details, as I don’t live in the US, Libre and Dex are two different things. Libre replaces the fingerpricking with scanning when you want to scan, while Dex is a real CGM giving you continous readings. It does require calibration, but it is also giving much better quality of readings as well.
You are correct about libre being more discrete, less invasive and less intruding on your life - since the size of sensors and the patch is smaller and you choose when you want to know the reading.

Choice? Question of taste.

Rich - it really depends on what your needs are. The biggest difference is auto-alarming on the Dexcom… I am in the U.S. and got my first Libre from Germany a few years ago when I saw it was available on Ebay.

For a T2 only using afrezza there is little concern for hypos. For me my goal was 24/7 profiling understanding how food, activity and afrezza affected my BG. For me it is six of one, half dozen of the other if the sensor auto-updates the reader. I am going to take the reader/phone out of my pocket anyway to look at it. Touching the sensor takes a few seconds. In my case I have little interest in alarming. Also, the Glimp app for my purposes is better than the Abbott reader and can auto-send to the cloud for long-term reporting. The Glimp app can also be calibrated and most think its much closer to a meter than the reader. You can also get the 14 days out of the sensor and the 1 hour warm-up as the “FDA fix” was changing the reader software.

For a T2 on another insulin than afrezza you have to weigh your need for alarming based on your hypo risk and after meal spiking. If you are going to check anyway 1, 2 and 3hrs after a meal anyway then you have to weigh that value.

Two advantages of the Libre are no daily fingersticks and cost depending on your insurance coverage. Using the Glimp a 3 sensor box at $129 will give you 42 days coverage at about $3 a day.

Here is a pretty good review from Gary Scheiner who is a T1 and extensively uses Dexcom in his practice and remotely reviews Dexcom profiles through the Dexcom cloud system.


I have no need for alarming and your situation sounds very much like mine. The Libre sounds right for me too.


Thank you very much for posting the link to the review by Gary :slight_smile:

I just started the free style sensor. I think that I might still have to finger stick sometimes, especially before I go to bed for the adjustments I need. But it is still too soon to tell how much I will still need to test.

If it is even close to telling me when I have finally started to come down on those days my numbers want to stay up there. Or give me an idea of if I’m 300 or 150 it will save my fingers and make me a happier person!

So if it even cuts down on 50% of finger sticking I will be happy! I haven’t ever used any other CGM so eventually I might switch. But right now I’m loving being able to wave something over the monitor and have an idea of what my blood sugar is doing!!!

But that could change lol…it’s very new to me right now!

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I’m on insulin, T2, and have recently tried out the Libre.

The bad:
When it’s off. .it’s way off. Finger prick will show 130, Libre will show 170 or higher. Today it was telling me 230 when I was 170 and hadn’t eaten in hours.

10 day limit on sensors and 12 hour warmup. This just offends me when the rest of the world gets 2 hours and 14 days. I have a cousin in Italy purchasing a reader for me to see if I can get around the limits of the US reader.

Insurance doesn’t seem to cover it yet. I pay $75/month at Walgreens for 3 sensors. Insurance denied the claim and this is what the pharmacy charged.

The in between
I would really like to have my readings on a smart watch, no other device required. But the tradeoff is a bulkier sensor and more cost for the Dexcom once it works with the Apple Watch.

I wish I could calibrate it even once a day to keep it more accurate. It tends to be pretty good closer to 80 and wanders off the higher I am.

The good
It’s pretty inexpensive compared to the alternatives and is very discreet. I keep mine on the inside of my arm and am on my second sensor now.

I have approval to get a Dexcom system and am torn on whether or not I will. I think I’ll hold out for the G6 and see if they keep the ability to restart the sensors which will affect my monthly expense. If I get the Italian Libre reader and it allows me 14 day sensors it will be hard to convince myself to switch.

My main question is whether or not the Dexcom would prove to be an appreciable amount more accurate than the Libre. When I’m in range the Libre works well. When I’m tipping higher it’s pretty useless which leads me back to finger pricks before taking a bolus.

If you are not pleased with the Libre, it might be worth giving the G5 a try now and see how long you get on the sensors? Particularly if you currently have insurance approval for the Dexcom system. Woud you have anything to lose?

When taking Dexcom sensor restarts into account, it certainly is possible the Dexcom could cost you less than the Libre. (Plus insurance coverage?) It is quite individual as to how long (past the initial 7 day session) a Dexcom G4/G5 sensor lasts for somebody.

At this point there is zero indication that the Dexcom G6 will NOT allow sensor restarts.
On the other hand, “seeing is believing” and the final answer of course will be clear when the G6 is launched after the FDA approval.

I think it’s just a cost thing right now. I just ordered the Italian Libre @ 60 euros and don’t have it yet. Insurance will cover some of the Dexcom but it’d be $480 up front and around $90/month (assuming I get 14 days out of a sensor). I’m going to ride the Libre out a bit I think. The main draw of the Dexcom is the calibration (if it really helps) and the smart watch integration. .which isn’t available yet. Also worried about the alarms that everyone seems to complain about. Need to see how they flesh out the smart watch integration if I can have it vibrate when it goes out of a range that I set then that’d be perfect.

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Please let us know if the Italian reader works with the US sensors.


Medicare covers the Libre as of this year-same cost/requirements.

Yes, I agree that Abbott has said that.

My only question here is I would be very interested to have a verified first-person report from somebody who has actually obtained a FreeStyle Libre with proper Medicare reimbursement.

I tend to be “show me” sort of person.



As of 2018 the Libre is covered by Medicare. It is smaller; but the cost is the same as Dexcom. If you are prone to hypoglycemia, however, especially at night, the danger is, there is no alarm to wake you. I tried both, simultaneously, and was finally awakened by the Dexcom at BG of 35. (I had the Dex under my pillow). Scarey to think what would have happened with just the Libre. Right now, you can try out the Libre for ten days, free. Look it up on the Libre site.

Unfortunately if you read the fine print on the Libre trial offer, Medicare beneficiaries are not allowed to participate.

With hardware, I like to use something that’s been around a long time so they have worked out the kinks. I believe that Dex is the industrusty standard/leader, so I try not to experiment with anything else. I’ve have great results from it.

The Libre has been around for a long time, just not in the US