FreeStyle Libre Sensor Safe Wear Time

Ok the FreeStyle Libre has arrived in the USA and should be on the market soon. My question is for anyone using the device. What is the safe wear time of the sensor? I know 10 days is the suggested time, but as we all know wear time for the Dexcom is what one can get away with. Planning on get me one until my G5 gets processed by Dexcom. Any information would be appreciated.


I can’t imagine a sensor from any company being limited to the “official” wear time, as you know those times are always super-conservative. If it becomes inaccurate (assuming for the moment, that it is accurate during the first 10 days), then of course you’ll want to replace it. It’s not like infusion sets–insulin entering the body at one point, over a period of time, causes scar tissue and absorption issues, so for that case, it is good policy to adhere to the suggested set-change intervals, usually 3 days max. No one is going to keel over if they extend to 4-5 days,but it’s not a great idea to be doing that due to the aforementioned issue with scar tissue.

ie, if cost is an issue I’d imagine patients will extend the wear time as much as possible, til inaccuracy rears it’s ugly head. If cost isn’t an issue, some folks will still extend wear time “just because”. :slight_smile:

Check some other posts on Tu. I think the sensor wont make it past ten days…think I saw that.

that could get expensive for those paying OOP.

IIRC, rumor(?) is that the Dexcom g7 will have limited wear-time. If true, that will also be a major bummer for those choosing to buy them OOP.

I heard they were going to make it so you could take Tylenol without throwing off Dex. If I can ever afford it, that will help me out!!

So Dave like the Dexcom sensor, if the Libre sensor is running ok at the end of the 10 day cycle, you can just restart it without a new sensor insertion and start a new cycle or end it if necessary. Obviously since I will pay out of pocket I would try for 15 days per sensor to save some money.


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today marks my longest functioning G5–16 days and counting. Most I’ve gone in the past is just 12 days.

I wear most of my Dexcom Sensors for 18-21 days and recently have gone 30 days. The Libre sensor will cut off at 10 days for US users. It is a software death and there is no way to extend,


There is no way to restart it unfortunately. It’s different than the Dexcom, the reader detects the specific sensor and will not let you restart one that is dead.

I think we should all be celebrating that there are at least two companies that are offering CGMs. And there are more in the pipeline. Next year and the year after that, there will be more and better choices. Both Dexcom and the Libre have a significant market share and are working actively to improve their product. And like a product on Amazon, there are many five star ratings and some number of one star ratings. If a company gets mostly one star ratings, it is likely to fail. But I don’t believe either current offering is in that situation. I look forward to continuing competition and better products down the road.

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Jenny Ruhl reviewed the Freestyle on her Blood Sugar 101 Facebook page.

So did Will Dubois and Six Until Me.

It’s my understanding that the Libre simply shuts down after 10 days.

That’s not very consumer-friendly and from what I’ve heard Dexcom is going the same route on the G7

Reviewers agree about Libre reading low.

From Kerri Sparling at Six Until Me:

My results seem to run on the lower side when compared to my Dexcom G5 CGM and my Freestyle Freedom Lite glucose meter. Like just now, my Dexcom said I was 146 mg/dL, my meter said I was 145 mg/dL, and the Freestyle Libre system said I was 113 mg/dL.

Wil Dubois, DiabetesMine:

In my two-sensor test-run of the Libre, a problem I found was the system’s accuracy.

After the first sensor booted up following the 12-hour warmup period, it was a full 20% lower than my Dexcom G5, which requires two calibrations per day that I perform with the highly regarded Bayer Contour Next strip. Yes, I know traditional meter accuracy can also be way off… but the Contour is 8.4% accurate compared to lab values and is the best we’ve got in consumer meters. That combined with the fact that my Dexcom results very accuately reflect my A1C, I’m pretty comfortable saying the Libre was way the heck off for me.

Before I could depend on the Libre, I would like to compare it to my glucose number in my quarterly labs.

What meter have you found matches lab results exactly? I’ve been using meters since 1992 and have NEVER found a matching random glucose reading from a meter to the lab results. EVER. From ANY meter and I’ve used countless brands and models. I’ll tell you what I trust more than anything: the readings from any Contour Next meter model. I’ve had just one flaky result in recent memory, and I mentioned it on this forum I think yesterday. Lab results have always read higher than finger stick readings, in my personal experience. Yet my A1c results are pretty darn good. the last one was 5.7. Usually I’m 6.1.

I’ve never had a meter match lab results exactly. But I have seen very good correspondence. Last June I did three fingersticks right after a lab draw. They came in at 80, 85, and 86 mg/dL. The lab came in at 82 mg/dL. I use the Accu-Chek Aviva Connect with Aviva test strips. This is the meter I use to calibrate my CGM.

Good to read about your favorable impression with Contour Next meter/strips.

Has anyone tried starting/reading the American sensors with a phone app? I’m wondering if that would allow you to avoid the 12-hr warmup and get more than 10 days out of a sensor.

This question may have been answered and I missed it, but will the 14 day sensor work with the USA Libre Reader? By the way ,nothing strange, but why did the FDA only approve a 10 day sensor and the rest of the world uses a 14 day sensor. Was this an accuracy issue?