FreeStyle Libre 2 and 3 vs Dexcom G6 Accuracy

I used the Dexcom G4, G5, and G6. I found the G4 and G5 to be inaccurate. I find the G6 to be fairly accurate. I found the FreeStyle Libre 1 to be inaccurate. I found the FreeStyle Libre 2 to be more accurate than the 1, but not great.

Personally, I’m a T1 with hypoglycemic unawareness. So, the alarm feature while I’m sleeping is really important to me.

The FreeStyle Libre 3 was approved in Europe recently, which has a continuous reading with alarms like the Dexcom G6. It may be available early next year (2021) in the U.S. The big difference is that the Libre 3 will be affordable out of pocket. I have not been able to get Medicare coverage for any of my devices including test strips. They keep saying that I don’t have any equipment that uses test strips. Maybe it is because I live in NY. The Omnipod is not covered by Medicare.

What is your experience and accuracy with devices you have used?

I have personally found the Eversense to be the most accurate, and then Dexcom. and libre, but have found all 3 are accurate enough for me with a slight 20 min delay if I’ve recently injected insulin or eaten a meal, however, I have found different medications such as ibuprofen, naproxen sodium, and antibiotics can drastically affect Dexcom and libre more…might want to look into contraindications

I use finger sticks for insulin dosing. I use the alarm to alert me to hypoglycemic attacks.


Dexcom G6 is covered by Medicare.

Prior to G6, dexcom G5 was also covered, but required bg meter checks, and dexcom would send both G5+contour next strips.

But since G6 uses a code per sensor, it is considered just as accurate as bg testing, and covered by dexcom.

Contact Dexcom to check why you are being told G6 is not covered.

To get coverage for test strips, you may have to first buy meter covered by your MC plan and then get strips under Part B.

Every time I talked to someone at Medicare, I get a different story. Other people in NY have similar problems.


i would try to ask for freestyle neo test strips because the libre 2 reader is also a freestyle neo glucometer… the libre 2 also frequently requests you to check your glucose, and it might be convenient since you have to have the libre 2 reader on you at all times… my drs offered to write a neo test strip prior authorization form since my current insurance company prefers one touch, but I rarely use them with the cgm

They won’t listen and don’t care. I have tried for years and I finally give up because it is too much aggravation. They get on the phone with an attitude that their coffee break is being interrupted.


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@DrJohn, I have been using G6 since it came out. I started with the Dexcom 7 in the early 2000s. I have continued to read peer reviewed journals, some juried included to harvest information about accuracy. Dexcom has always been the leader on accuracy.

The only down side is the range. I was hospitalized and had daily chem panels with glucose determinations. I had my G6 on. The serum glucose was consistently 14 mg/dL lower than the Dexcom at the time of the venipuncture. The nurses were impressed.

Hope this helps. Let us know what you decide. It is how this community learns.

I used the 10 day Libre for about a year. It was terribly inaccurate but was of value to me to know what direction I was heading. Was it still climbing? Had I reached the peak? Was my insulin finally kicking in? I just ignored the actual “numbers” and used the graphs for information. The numbers were always much lower than reality. They were anywhere from 25 to 60 points below reality.

When the Libre 14 day was approved for the USA, I tried it for about 6 months. Same inaccuracies.

I just got my first Dexcom., the G6, and I am on day 8 of my first sensor. It has been spot on with accuracy. The largest discrepancy I have encountered so far has been 2 points.

If the Libre had the accuracy of the Dexcom G6, I would be thrilled. Wish I could combine the two. There are a lot of things I like about the Libre, I just don’t like seeing a good number when it is false.

Anyone know if the Libre 2 is more accurate than the prior Libre products? Or did they just add alarms?

I haven’t found the Libre 2 to be any more accurate than the Libre 10 day. I wear both a Dexcom and a Libre2. I use the Libre2 for swimming and only basically look at it while I am out in the water. I would find the Libre still invaluable except I have a Dexcom.

For example, right now my Contour meter says 135, my Dexcom says 133 and my Libre says 120.

I will probably switch to the 14 day Libre as for my purposes I don’t need the alarms the Libre 2 has, and I believe after Jan 1st the price went up on the LIbre 2 as a coupon I had from Abbot expired.

i feel the accuracy is the same, they just added alarms, for some diabetics, especially type 2 or anyone who’s not used to seeing their glucose numbers on their watch at all times, its a huge advantage… its also OK for most children where the libre 1 was not… I find the accuracy to be good enough and worth the price difference between Dexcom… it will stay low a lot longer than the Dexcom or Eversense, and it doesn’t work on any phone, only the reader

I used the Dexcom G5 for over a year, but I was paying out of pocket for it. So when I got a prescription for the Libre 14 day with insurance helping pay for it, I was really excited. Unfortunately after using it for a few months I gave up on it. I had too many issues with the accuracy. I also noticed for myself, and after looking around online this seems to be common, the back of my arms didn’t have enough fat on them to put the sensor there. I had better luck putting it on my thighs but not being able to calibrate it made me give up. Now I’m on the Dexcom G6 and having much better experience with the calibration. I just got on new insurance so I still need to see if I can get coverage for it. Otherwise it might be temporary … I kind of wonder if body type plays a role in who has a better experience with Dexcom vs Libre.