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FreeStyle Libre Shines in Type 1 Diabetes Study: A Decrease of 74 Minutes Per Day Spent in Hypoglycemia

Strong results from the IMPACT study in low-A1c users.

At the ADA Scientific Sessions in New Orleans, Abbott shared results of the IMPACT study, a randomized six-month trial comparing the FreeStyle Libre “flash glucose monitor” to fingersticks in people with type 1 diabetes (see more on how the Libre works here). The trial recruited 241 participants with an average starting A1c of 6.7% (considered “very good control”) and lots of hypoglycemia at the start of the study (~200 minutes per day!). Compared to the fingerstick group, those using FreeStyle Libre spent significantly less time with low blood sugars – both during the day and at night:

  • A decrease of ~74 minutes per day in hypoglycemia (under 70 mg/dl) – a 38% reduction
  • A decrease of ~33 minutes per day under 45 mg/dl – a 60% reduction
  • A decrease of ~28 minutes per night with nocturnal hypoglycemia – a 40% reduction

There was not a significant difference in A1c between the groups by study end – both saw a very small 0.15% increase from baseline to six months (6.7% to 6.9%). The “quality” of A1c based on time in range, however, definitely improved on Libre: a decrease of 22 minutes per day in severe hyperglycemia (above 240 mg/dl), and an increase of ~60 minutes per day spent “in range” (between 70-180 mg/dl).

FreeStyle Libre essentially replaced fingerstick testing, suggesting a high level of confidence in the accuracy of the “no calibration” sensor. Fingersticks with FreeStyle Libre fell from an average of ~5.5 tests/day at baseline to 0.5 tests/day (one every two days) at six months. But those on the Libre scanned their glucose data 15 times per day on average – certainly giving them more data than just five fingersticks per day. Quality of life data was also significantly in favor of FreeStyle Libre – with participants reporting greater treatment satisfaction on the Libre. [How was hypoglycemia, time-in-range, and hyperglycemia measured in the fingerstick group? They wore a blinded sensor to capture the data at baseline and at a few points throughout the study.]

The nighttime results help counter the argument that Libre’s lack of alarms poses a danger. There is now solid evidence from two studies that Libre can help patients and providers identify some nighttime hypoglycemia and make changes accordingly.

IMPACT highlights the daunting amount of hypoglycemia those on insulin therapy (type 1 in this case) are experiencing every day. It is also a reminder of the tremendous challenges of dosing insulin as A1c approaches 7%. Patients at baseline were spending ~200 minutes per day – more than three hours – under 70 mg/dl! The hypoglycemia improvement with FreeStyle Libre was very meaningful (-74 minutes per day), and there is still room to improve further: patients on Libre were still spending two hours per day less than 70 mg/dl at six months. Meanwhile, patients using just fingersticks were still spending over three hours <70 mg/dl per day, no change from baseline. In that sense, the results tell us as much about FreeStyle Libre’s ability to reduce hypoglycemia as they do about the real-world dangers of insulin therapy, especially in “well controlled” patients; three hours per day in hypoglycemia is downright dangerous. At the same time these patients would be congratulated for getting below 7%. Avoiding lows on insulin therapy is truly difficult as A1c gets below 7%, and we’re not sure that delicate balance is appreciated enough.

These results also underscore the limitations of using A1c as the sole measure of good glucose control. Both groups saw a 0.15% increase in A1c in this study, though the quality of A1c improved markedly in the FreeStyle Libre group with significant reductions in hypoglycemia and more time-in-range. Meanwhile, the control group was still spending three hours per day in hypoglycemia with a “good” A1c 6.9%. Will the FDA and insurance companies appreciate the “higher quality” A1c outcomes that next-gen devices and drugs might bring?

The IMPACT study follows the REPLACE study, which studied the Libre’s impact on A1c in people with type 2 diabetes and high baseline A1cs. Unfortunately, the Libre did not significantly reduce A1c in that study, though it did reduce hypoglycemia and improve quality of life as well (read more here).

Abbott has broken the mold in glucose monitoring by conducting now two long-term outcomes studies (IMPACT and REPLACE) of FreeStyle Libre. There is a wealth of evidence here that more frequent glucose data is beneficial for patients and providers, and that A1c is not the only relevant measurement in clinical studies and real-world patient experience.

When is FreeStyle Libre Coming to the US?

FreeStyle Libre (real-time version for patients) is currently available in several European countries and Australia, but it is not clear when it will launch in the US. We learned at ADA that Abbott has not yet submitted it to the FDA, meaning it likely won’t be out until 2017 or later. By contrast, FreeStyle Libre Pro (blinded, retrospective, placed in a healthcare provider’s office) has been under FDA review since mid-2015, with approval hoped for the middle of this year (yes, any minute!) in the US. More on that here. -AB/AJW

[Photo Credit:]

flash glucose monitoring
Type 1
Freestyle Libre
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Type 1

Comparing FreeStyle Libre vs. Fingersticks in Type 2 Diabetes

At the AATD Conference, Dr. Thomas Haak shared long-awaited results from Abbott’s FreeStyle Libre REPLACE study. The six-month trial compared use of the “flash glucose monitoring” system FreeStyle Libre (see more on how the Libre works here) to standard fingersticks in type 2 patients on basal-bolus insulin therapy. The study enrolled patients with an average A1c of 8.8%, aiming to show that FreeStyle Libre (and the 24-hour per day data that comes with using the sensor) can improve A1c much more than taking just four fingersticks per day. REPLACE also measured rates of hypoglycemia and quality of life. The key findings:

  • Disappointingly, the study missed its primary goal, demonstrating similar 0.3% A1c improvements in both groups. On the plus side, users under 65 years old saw a greater A1c improvement with FreeStyle Libre (-0.5%) than with fingersticks (-0.2%).

  • FreeStyle Libre dramatically reduced hypoglycemia by more than 50%. Relative to fingersticks, patients using FreeStyle Libre spent ~30 minutes fewer per day less than 70 mg/dl, and ~13 minutes fewer per day in very dangerous hypoglycemia less than 55 mg/dl. Compared to the study start, those translated to 55% and 68% reductions, respectively, in FreeStyle Libre users.

  • Nighttime hypoglycemia similarly improved with FreeStyle Libre, which is important, given the absence of alarms on the device. We assume the retrospective glucose data helped patients and providers identify nocturnal hypoglycemia.

  • FreeStyle Libre improved quality of life and patient-reported outcome measures. Two different measurements of quality of life (the Diabetes-Treatment-Satisfaction Questionnaire and the Diabetes Quality of Life survey) showed an increased overall satisfaction for FreeStyle Libre vs. taking fingersticks.

These results serve as a reminder of how much hypoglycemia impacts type 2 diabetes, and more important, how challenging it is for diabetes technology to improve A1c AND reduce hypoglycemia at the same time – cutting down on lows is a good thing, but it unfortunately raises average glucose (and thus A1c).

It’s worth noting that the study design did not tell providers and patients what to do with the comprehensive glucose data from FreeStyle Libre (a real-time glucose value taken every minute, 24 hours per day). That was a deliberate decision to ensure a real-world trial, though it may have impacted the results. For instance, the FreeStyle Libre download software very clearly points out hypoglycemia with a red traffic light. Were patients on FreeStyle Libre and their providers surprised to find lots of unrecognized hypoglycemia, prompting them to reduce insulin accordingly? This is of particular concern in older patients, the very same population that did not see an A1c benefit in this study. Of course, it is also much easier to fix hypoglycemia (reduce insulin) than to safely bring average glucose down (“Is it correction or food bolus? Or is it basal? Or is it...”).

It will be interesting to compare these results to the type 1 study, IMPACT, which will be presented at a conference this June. That trial’s goal is to show reductions in hypoglycemia in patients with an A1c of less than 7.5%, which seems like a given after REPLACE. The ultimate hope is to use the results from these two studies to support European reimbursement of FreeStyle Libre. As a reminder, patients currently pay (out of pocket) 59 euros (about $66) for each 14-day FreeStyle Libre sensor, and 59 euros for the touchscreen reader. That is cheaper than CGM, but more expensive than blood glucose test strips.

It’s not clear when FreeStyle Libre (real-time version for consumers) will launch in the US. Abbott’s CEO recently said that it might be available by the end of 2016, though this statement was ambiguous, and we’re not sure if FreeStyle Libre (consumer) is even under FDA review. By contrast, FreeStyle Libre Pro has been under FDA review (blinded, retrospective) since mid-2015, and this should launch sometime this year. More on that here.

All things considered, we salute Abbott for conducting this ambitious, long-term outcomes study of FreeStyle Libre. The ultimate mark of any technology is whether people will buy it, and FreeStyle Libre has no issues there – demand has been off the charts since it launched in Europe in fall 2014.

Other FreeStyle Libre Updates:

  • Abbott obtained European approval to market FreeStyle Libre in children ages four and up. We’ve heard that many children in Europe are already using this device “off-label,” though this official approval is certainly great news for helping more kids get access to this new technology.

  • FreeStyle Libre will be available in Australia in the coming months, expanding its availability from the following 11 countries: Austria, Belgium, France, Germany, India – Pro version, Italy, Netherlands, Norway, Spain, Sweden and the UK. 

flash glucose monitoring
Type 1 & Type 2
Freestyle Libre
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LibreLink: Scanning the FreeStyle Libre Sensor Straight From A Smartphone

Twitter summary: LibreLink app reads Abbott's FreeStyle Libre sensor with a smartphone

Abbott recently announced the launch of LibreLink in Sweden*, a free Android app for scanning the 14-day FreeStyle Libre sensor. This important advance eliminates the requirement for the separate touchscreen reader and further builds on the “Libre” name – freedom from fingersticks, and now, freedom from an extra device! The app is available on the Google Play store in Sweden, and Abbott told us that more European launches are planned for 2016, including France, Germany, Netherlands, Italy, Spain, and the UK. (See our previous Test Drive for background on how the 14-day, no fingersticks FreeStyle Libre system works). Currently, LibreLink is the only mobile app that has been approved to work with FreeStyle Libre sensors.

The LibreLink app, developed by AirStrip, functions just like the FreeStyle Libre reader. Once it is installed on an Android phone, a user can start a 14-day sensor and obtain real-time glucose information by briefly holding the back of the phone near the sensor, just as one would do with the reader. The app then immediately shows the current glucose reading, trend arrow, and eight-hour history. The app doesn’t have to be open to initiate the scan process – very convenient! – though the phone must be unlocked. The FreeStyle Libre sensor can only link with one device, so people must decide whether they want to use the touchscreen reader or the LibreLink app over the 14 days of wear – unfortunately, you cannot tradeoff between the two devices.

For now, LibreLink is only available for Android phones with built-in NFC (most models have this, including the popular Samsung line). An iPhone version is in the works, but there is no information on when it will be available - we imagine there will be high demand for this as as more people in the EU are buying iPhones

What are the advantages of the LibreLink app over the reader?

  • Lower cost – the app is free, eliminating the 59.95 euro ($64) startup cost of the touchscreen reader. Each 14-day sensor still costs 59.95 euro ($64).

  • Convenience – it eliminates the need to carry around a separate receiver.

  • Colorful design – LibreLink maintains the same excellent report features from the FreeStyle Libre reader, but in a more visual, colorful design.

  • Improved data sharing – data is saved directly into the app and allows users to email reports directly from the phone. This eliminates the requirement to plug in the reader to a computer (though with a USB cable, that's pretty easy too!).

One advantage of the FreeStyle Libre reader compared with LibreLink that we can think of is the frequency with which the devices need to be charged; the reader needs charging about every 4-5 days, while phones generally need to be charged daily. While we don't anticipate this being a major problem, it does increase the chance of someone being caught with no data due to a dead phone. 

How does LibreLink compare to the Dexcom G5?

The FreeStyle Libre has several key differences from the Dexcom G5 Mobile System and continuous glucose monitoring in general (see our guide: How is FreeStyle Libre Different from Continuous Glucose Monitoring?). However, since both devices now offer smartphone apps that completely replace a separate handheld device, we think it’s useful to compare them. Some key points of differentiation are below. [Note: We’ve excluded Medtronic’s MiniMed Connect, since smartphone viewing requires both the pump and the separate keychain device.]


FreeStyle Libre + LibreLink

Dexcom G5

Viewing Flexibility

Each 14-day sensor links with one device – must choose between the reader or app

Each seven-day sensor pairs with two devices. Can trade off using the receiver or G5 app.

Current Phone Compatibility

Android, no word on when Applie iOS is expected

Apple iOS, Android expected early 2016

Obtaining a Reading

LibreLink app does not have to be open to obtain a glucose reading – if the phone is unlocked, the reading will come up on screen automatically after the sensor is scanned by the smartphone.

G5 requires unlocking the phone and manually opening the app to view the glucose reading.

Purchase Requirement

Not required to purchase the FreeStyle Libre reader device (we view this as a meaningful advantage).

Must buy the G5 receiver, even if it is not used.

Transmitter Use

The 14-day-wear FreeStyle Libre sensor/transmitter is fully disposable

G5 Bluetooth transmitter lasts three months. Seven-day sensor is disposable.

When is FreeStyle Libre coming to the US?

There is no updated timing on an FDA submission of the real-time, consumer version of FreeStyle Libre. As we noted in August, the blinded professional version of FreeStyle Libre is under FDA review, with a potential US launch in 2016. Results of one of the two big Abbott trials will be given at ATTD in Milan in February. 

FreeStyle Libre Pro is a bit different from the patient version of FreeStyle Libre discussed above. The Pro version is blinded (no reader device or app) and allows physicians to get continuous glucose data from patients over a two-week period. After applying the Libre Pro sensor in the doctor’s office, it is worn for two weeks, and the sensor automatically records glucose values every 15 minutes. Patients then return to the doctor’s office, where the sensor is downloaded.

We’re hopeful that a future FDA submission of FreeStyle Libre includes the LibreLink app – many patients will appreciate the convenience and user experience advantages! –AB/AJW

* Correction: After hearing from readers in Sweden that the app is not yet publicly available, we received clarification from the team at Abbott: LibreLink has initially been launched on an invite-only basis, and will become more widely available in early 2016.

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flash glucose monitoring
Type 1 & Type 2
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Adam Brown

The Latest European Experiences with Abbott’s Groundbreaking FreeStyle Libre System

Twitter: Valuable, exciting testimony at #ATTD2015 on #FreeStyleLibre glucose monitoring system, + updates on accuracy + pricing!

At this year’s ATTD Conference in Paris, a good deal of excitement centered on Abbott’s FreeStyle Libre glucose monitoring system, which launched in Europe last October. The 14-day sensor and touchscreen reader is intended to replace glucose meters, but provide CGM-like information (real-time reading, trend arrow, history). In line with our positive experience wearing the system, the Libre has been a major hit in Europe, and Abbott’s biggest challenge is actually meeting demand. While there weren’t many new tech updates on the Libre at ATTD, we did learn more about the system’s accuracy and how patients and health care providers like it.

FreeStyle Libre is Accurate in Hypoglycemia

New data presented at ATTD suggested that the Libre’s overall rate of accuracy is ~12% vs. a lab analyzer (e.g., if blood glucose is 100 mg/dl on average, the system would be off by about 12 mg/dl on average). This was identical to the real-world accuracy we find vs. a blood glucose meter. It’s remarkably strong considering FreeStyle Libre does not require any blood glucose meter entries (calibrations) to begin reading glucose values – it’s “factory calibrated.” Results also showed that the Libre maintains its accuracy when glucose levels are rapidly changing, as well as during periods of hypoglycemia (glucose levels between 50-80 mg/dl). For comparison, Dexcom’s G4 Platinum with the new Software 505 update has better accuracy at 9.0%, though it requires two calibrations per day; Medtronic’s Enlite sensor comes in at ~14% and requires 2-4 meter calibrations per day.

First-person testimonies on FreeStyle Libre really put the accuracy into perspective. Dr. Iain Cranston (Portsmouth Hospitals NHS Trust, England) said, “Half my patients have not done a fingerstick in two months. They come to rely on Libre… This should pass as a glucose meter. It meets all the criteria.” We note that the Libre’s guidelines officially recommend that glucose levels be verified in a few cases: when hypoglycemic (low), rapidly changing, or when symptoms don’t match the system’s readings. However, the anecdotal evidence at ATTD suggests that many patients are relying completely on the system. An accuracy trial for Libre is now underway in the US, which could help lead to future US approval.

Do Patients Think FreeStyle Libre is Easy to Use?

New user experience data from a 72-person study was presented at ATTD, emphasizing the Libre’s convenience and comfort. Of those studied:

  • 100% agreed that the sensor was easy to apply.

  • 96% agreed that Libre is comfortable to wear.

  • 88% agreed that applying the sensor was less painful than a routine fingerstick (more to the point, we’d add that insertion is only required once every 14 days).

  • 86% agreed that the sensor did not get in the way of daily activities.

The Libre is currently only approved for wear on the upper arm, although commentary at ATTD sessions suggests that many patients are experimenting with the sensor’s placement (e.g., buttocks, abdomen), with no noticeable change in accuracy (this is only anecdotal).

What are the Libre’s Adverse Effects?

In the same study, 26 of the 72 volunteers reported some level of discomfort around the sensor insertion site, though all reports were consistent with what would be expected following insertion of a sensor into the skin. There have also been patient reports of mild allergic reactions to the sensor (you can see this on twitter), resulting in skin rashes and irritation, but from our understanding, these instances are rare and most often relatively mild.

Pricing Updates for the Libre

At ATTD, Dr. Cranston approximated that the cost of FreeStyle Libre is equivalent to using ~10 test strips per day. As a reminder, FreeStyle Libre costs 60 euros for each 14-day sensor (120 euros per month), significantly cheaper than CGM. Abbott continues to work on obtaining insurance coverage for Libre (additional studies are still ongoing in type 1 and type 2 diabetes), with expected primary completion dates in May 2015. –AB/AJW

flash glucose monitoring
Type 1 & Type 2
Freestyle Libre
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Adam Brown

Abbott’s FreeStyle Libre – Transforming Glucose Monitoring Through Utter Simplicity, Fingersticks Aside!

by Adam Brown and Kelly Close

Twitter Summary: Wearing Abbott’s #FreeStyleLibre, a 14-day sensor intended to replace glucose meters, but provide CGM-like info; now available in Europe

Want more info like this?

In October, Abbott launched its highly awaited FreeStyle Libre Flash Glucose Monitoring system in Europe. The unique product is intended as a replacement for blood glucose meters, while giving patients many of the benefits of continuous glucose monitoring (CGM), including real-time glucose values, trend information and comprehensive reports. Though it is not yet approved in the US, we were able to test the product over the past month (the device can only be ordered online from websites in Europe). 

Given what we had heard from so many European bloggers, we had high expectations going into our test, and FreeStyle Libre absolutely met them at every step – the system was  easy to setup and use (a major win for healthcare providers); discreet to wear on the upper arm; accurate enough from which to dose insulin, with performance similar to Dexcom’s G4 Platinum CGM (though no fingersticks were required); and it gave an excellent picture of glucose trends through real-time and on-device reports. In short, it is transformative compared to the limited information provided by traditional blood glucose meters, all in a package anyone can pick up and learn to use. We give FreeStyle Libre an emphatic thumbs up and would recommend it to nearly anyone with diabetes, especially those on insulin who test their blood glucose frequently and want more actionable information than fingersticks alone can provide. One key point of difference from CGM is that FreeStyle Libre does not have high or low alarms, meaning it is not as ideal for those with lots of hypoglycemia or hypoglycemia unawareness.

This article discusses our experience wearing and using the device, its accuracy compared to the Dexcom G4 Platinum CGM, how European readers can get it, when we might see it in the US, and how it’s different from CGM.

Table of Contents

How the FreeStyle Libre Works

FreeStyle Libre includes a very tiny glucose sensor (0.2 inches in length, about the thickness of a hair) worn under the skin and connected to a water resistant, plastic on-body patch the size of a one-dollar coin. The sensor remains inserted for 14 days and does not require fingerstick calibrations (it’s “factory calibrated”). After putting it on the upper arm and waiting one hour, it immediately begins reading glucose and trend information. FreeStyle Libre is approved for dosing insulin except in three cases when a fingerstick is recommended: when hypoglycemic, when glucose is changing rapidly, or when symptoms don’t match the system’s readings.

To use FreeStyle Libre, users take a touchscreen reader device, hold it near (within 1.5 inches) the sensor patch, and wait for it to beep. In less than a second, they can see their real-time glucose value (e.g., 102 mg/dl), a glucose trend arrow (e.g., rising), and a trend graph showing the last eight hours of data. The reader device displays reports on its screen that can be downloaded to Mac and PC-compatible software. The system is currently available in Europe (pricing information below) for people with both type 1 and type 2 diabetes. Abbott does plan to bring it to the US, though we estimate it won’t come stateside until at least mid-2016.

Inserting, Starting, and Wearing the Sensor Patch


  • No fingerstick calibrations and only a one-hour startup time

  • Smaller, less painful sensor than traditional CGM

  • Very simple insertion process does not require training

Each 14-day sensor patch comes with a simple applicator to apply it to the upper arm. The insertion process took us less than 15 seconds, could be done with one hand, and passed the no-instruction-manual test with flying colors – (i) press sensor onto applicator; and (ii) press applicator onto upper arm. Pain wise, Kelly found the upper arm insertion completely painless, and she tends to be very pain sensitive. Adam experienced a bit of pain, as the spot he chose did not have very much subcutaneous fat. However, for both Adam and Kelly, insertion was much easier, more intuitive, and less painful than inserting the Dexcom G4 Platinum and Medtronic Enlite sensors. The FreeStyle Libre sensor is very tiny – only 0.2 inches – making it over three times shorter (roughly) than the Dexcom and Medtronic devices.

Once inserted, starting the 14-day sensor only requires three steps: (i) tap “start sensor” on the touchscreen reader; (ii) hold the reader within 1.5 inches of the sensor (to “scan” it); (iii) wait one hour. Once the 60-minute countdown ends, the system gives real-time glucose values and trend information. No glucose meter values required!

While the upper arm seems like a very noticeable and perhaps annoying location, the sensor patch is so small and light that we forgot we were wearing it. The low profile patch also comes with very, very sticky adhesive. Kelly’s sensor stayed on for all 14 days, and once the sensor session ended, it required a bit of force to remove. Adam’s sensor fell off on day 13, and he tends to be very active; by contrast, his Dexcom sensor only lasted until day 11, and that required additional taping. Abbott is pursuing approval for alternate wear locations (e.g., stomach, thigh) that could be more discreet.

Scanning the Sensor to Obtain Glucose Data


  • Scan process takes less than three seconds and works through clothing

  • Fun quality and cool factor associated with each scan

Unlike traditional CGM, FreeStyle Libre does not continuously send real-time glucose data to the reader; rather, the sensor patch must be “scanned” with the reader to obtain the real-time glucose value, trend arrow, and trend graph. The sensor patch stores up to eight hours of glucose data at a time (values are taken every minute). Adam averaged 11 scans per day during his wear and captured nearly 100% of the glucose data. Like viewing data on a CGM receiver, there is no limit to the number of scans that can be taken.

Abbott did an outstanding job of designing the scanning process to take less than three seconds. Hitting the single button on the touchscreen reader immediately turns it on and brings up the “Scan Sensor” menu. From there, holding the reader within 1.5 inches of the sensor obtains the real-time value/trend and past eight hours of glucose information (displayed on a line graph, just like traditional CGM). The scanning process works through many layers of clothing, allowing for excellent discretion and flexibility. From the home screen, you can also add tags to each scan, such as carbs, insulin, exercise, and customizable options.

There is a certain fun quality, cool factor, and psychological pleasure to scanning the sensor patch. Each scan is accompanied by an encouraging “ding” sound, followed by seeing the data on the reader. It feels almost like magic to be cheating the hassle of traditional blood glucose meters, especially because there is no limit or cost associated with additional scans. And importantly, FreeStyle Libre displays the number and trend arrow in black, no matter how high or low it is – it’s a very non-judgmental product, which takes some of the stress away from obtaining such detailed glucose data. Hypoglycemia is appropriately shown on the trend graph in bright red, however, to call attention to it.

Accuracy and How it Compares to Dexcom's G4 Platinum


  • Comparable accuracy to Dexcom G4 Platinum (including in hypoglycemia), but without need for fingerstick calibrations

  • Accurate and reliable enough for dosing insulin

Overall, FreeStyle Libre’s accuracy was downright impressive and seemed reliable enough for dosing insulin. To test real-world accuracy, Adam wore the FreeStyle Libre at the same time as a Dexcom G4 Platinum sensor (calibrated twice per day). He compared the real-time information generated by both devices to 46 blood glucose meter values taken over two weeks. On average, FreeStyle Libre was only 12% different from the meter value, very similar to 13% for the Dexcom G4 Platinum (note: Adam was not using Dexcom’s new 505 software, released in November, which does improve the G4’s accuracy). In addition, both devices had a similar number of sensor values that were more than 20% off from the meter value (seven with FreeStyle Libre vs. eight with Dexcom).

FreeStyle Libre’s accuracy was also strong in hypoglycemia. Adam experienced nine blood glucose readings <80 mg/dl over the two-week period, and on average, FreeStyle Libre was about 11% off vs. 8% for the Dexcom G4 Platinum. Lag time between the meter value and the sensor value was similar with FreeStyle Libre and the Dexcom G4 Platinum – about five to ten minutes at most.

The sensor technology in FreeStyle Libre is based off the highly accurate FreeStyle Navigator CGM, which originally launched in the US in 2008 and was discontinued in 2011. With that in mind, we weren’t too surprised to see the new device’s strong accuracy. However, the fact that FreeStyle Libre maintains the accuracy of the Navigator  - but without fingersticks – represents a major accomplishment.

Touchscreen Reader


  • Simple menu structure and intuitive navigation

  • On-device reports provide outstanding overview of recent glucose history and problem areas.

The FreeStyle Libre reader takes Abbott’s FreeStyle Insulinx meter and adds a sharp color screen. The reader is small, light, and easy to navigate with a touchscreen, icon-based interface (check glucose, history, and settings). It has a micro-USB port for recharging (we only needed two charges over two weeks of wear, though this depends on usage), and it can be downloaded to Mac or PC software. The reader also includes a built-in FreeStyle blood glucose meter for the few cases where Abbott recommends a confirmatory fingerstick (hypoglycemia, fast rates of change, when symptoms don’t match the reader).

The highlight of the reader is unquestionably the history menu, which includes a slew of excellent reports to understand glucose trends and problem areas. Our favorites:

  • Time-in-target – A valuable high-level overview of the percentage of the past 7/14/30/90 days spent above, below, and in target. Key for determining if hypoglycemia or hyperglycemia is generally an issue

  • Average Glucose (displayed by time of day) – A great way to see if one six-hour chunk of the day is particularly problematic.

  • Low Glucose events (displayed by time of day) – Again, an excellent way to see if one six-hour chunk of the day is contributing a lot of hypoglycemia

  • Daily pattern – A shaded 24-hour trend graph that makes clear the times of day with the most outlier high/low values.

  • Daily graphs – An awesome way to scroll day-by-day and see the 24-hour trend graph obtained on that day.

In presentations leading up to the launch, Abbott also promoted the Mac- and PC-compatible software that comes with FreeStyle Libre. The software seeks to simplify glucose data analysis, both through a traffic light system (to identify problem areas) and a single one-page report called the Ambulatory Glucose Profile. The goal is to equip healthcare providers and patients with simple tools to better tailor and individualize their therapy. Unfortunately, we were not able to download the software for this test drive, but look forward to trying it in the future. 

Cost and How to Get It in Europe

FreeStyle Libre is available at online web-shops in seven European countries: UK, France, Germany, Italy, the Netherlands, Spain, and Sweden. The touchscreen reader (one time cost) and each 14-day sensor cost €59.90 (~$77 US) – significantly cheaper than paying cash for traditional CGM although definitely more expensive than several strips a day (what is covered for many type 2 patients). Notably FreeStyle Libre does not require a prescription in the EU. Payment for the system is out-of-pocket right now, though Abbott is currently enrolling participants for two clinical trials that should help support reimbursement throughout Europe. Do you want one? If so, you need a friend with a credit card based in one of the countries that it’s available, plus their ability to access the Freestyle Libre website in that country – plus, the ability to pay for this fascinating technology.  

When is FreeStyle Libre Coming to the US?

Abbott is currently conducting an accuracy study of FreeStyle Libre in the US – more information is here. The study is expected to be completed in March. Abbott would then need to secure FDA approval of FreeStyle Libre, which would likely take at least 12 months. We imagine that at the very soonest, FreeStyle Libre could come to the US in mid-2016.

Appendix: How Is FreeStyle Libre Different From Continuous Glucose Monitoring (CGM)?

FreeStyle Libre incorporates elements of continuous glucose monitoring, such as a sensor placed under the skin, glucose values taken every minute, trend arrows, and downloadable data. However, it is really a new category of glucose monitoring that is meaningfully different from CGMs offered by Medtronic and Dexcom:

  • FreeStyle Libre does not have alarms or alerts, since the glucose sensor data is not sent continuously to the reader device. Rather, a scan of the sensor patch using the reader obtains the glucose data and trend information. By contrast, traditional CGMs continuously send the glucose data to the receiver/pump, allowing low, high, and rate-of-change alerts. This makes CGM a more attractive choice for those with lots of hypoglycemia and hypoglycemia unawareness. However, those who are bothered by lots of alarms might prefer the design of FreeStyle Libre.

  • FreeStyle Libre is “factory calibrated,” meaning users don’t have to enter any blood glucose meter values into the system. After the sensor is started and worn for one hour, it can show glucose data points and trends. Conversely, Medtronic and Dexcom CGMs require startup calibration, as well as daily calibrations to maintain the sensor’s accuracy. Factory calibration represents a highly impressive R&D achievement.

  • FreeStyle Libre is approved for dosing insulin except in three cases: when hypoglycemic, when glucose is changing rapidly, or when symptoms don’t match the system’s readings. In these cases, Abbott recommends confirming the value with a fingerstick. By contrast, Medtronic and Dexcom users are currently supposed to confirm every CGM value with a fingerstick before dosing insulin.

  • At just €59.90 (~$77 US) for the touchscreen reader and each 14-day sensor, FreeStyle Libre has a much lower cost relative to current CGM. For example, Dexcom charges ~$885 for the starter kit and ~$72 per seven-day sensor. Most US patients have reimbursement for CGM, so they pay less than that price; however, most European patients don’t have reimbursement for CGM, making FreeStyle Libre’s affordable price that much more notable. Abbott is currently conducting two studies to support reimbursement.

  • FreeStyle Libre does not require a prescription and can be ordered online. Dexcom and Medtronic CGM both require a prescription and have a longer on-boarding process (training, insurance verification, phone calls, etc.).

Type 1 & Type 2
Freestyle Libre
test drive
Our test drive of Abbott's FreeStyle Libre
By: Adam BrownKelly Close