Freestyle Libre: A Glucose Meter Without a Finger Prick

The Continuous Glucose Monitor Reinvented

continous glucose monitor
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In This Article

Blood glucose monitoring is a critical component of diabetes management, especially for people with type 1 diabetes and for those who take insulin. Regular monitoring makes diabetes management easier but can be intensive and invasive. Continuous glucose monitors can simplify this process by not requiring multiple fingersticks. Blum A. Freestyle Libre Glucose Monitoring System. Clin Diabetes. 2018;36(2):203-204.


The American Diabetes Association suggests that most patients using intensive insulin regimens, such as multiple insulin injections or insulin pump therapy, perform self-monitoring of blood glucose (SMBG) prior to meals, snacks, and exercise; at bedtime, occasionally after meals when they suspect low blood glucose, after treating low blood glucose until their blood sugar has reached a normal level, and prior to critical tasks such as driving.

It has been reported that those people who test their blood sugar more often have lower A1Cs and less glucose variability. But, you can imagine how intensive this can be—multiple fingerstick checks can be time-consuming, painful, and difficult to manage.

How It Works

In addition to SMBG, many people with diabetes may decide to use a continuous glucose monitor (CGM) to retrieve more information about their blood sugar so that they can better manage their medications, exercise, and food.

The Freestyle Libre System uses the latest technology to provide real-time glucose readings every minute using a pre-calibrated sensor (you do not have to calibrate it with a fingerstick; this is done in the factory). Unlike other CGMs, there is no bulky transmitter; instead, the small, water-resistant sensor (roughly the size of two stacked quarters) is inserted easily five millimeters under the skin on the back of the arm. The sensor measures the interstitial fluid, which is comparable to capillary blood.

Timing and Duration

After a one-hour startup period, you can retrieve a blood glucose reading instantly by scanning the sensor with your smartphone app or reader. You can scan as often as you'd like, but in order to capture all data, it is recommended that you scan your sensor at least once every eight hours to record 100 percent of the data. Studies conducted by Abbott, the maker of the Freestyle Libre, have demonstrated that people who use this sensor wind up scanning the sensor more often than they would test their blood sugar with a fingerstick, which provides them with more accurate data.

The Libre has the ability to store 90 days' worth of data. It can be worn up to 14 days—it stops working after this time period and must be replaced. Once you are finished with your sensor, you can dispose of it.

Manual Glucose Testing May Still Be Necessary

The Libre also has a blood glucose meter within the system. You might be thinking to yourself, why would I manually test my blood sugar if my CGM is checking it every minute? For starters, you might be curious if the CGM is accurate. In addition, there are certain times when the CGM can yield inaccuracies—this may be during a rapid change in blood glucose, such as after eating, dosing insulin, or exercising. Severe dehydration and excessive water loss may also cause inaccurate results. During these times, you'll need to confirm your blood sugar level with a fingerstick.

Sometimes, the Reader will not be able to let you know where your glucose is trending and will provide you with a warning symbol. Whenever you see this symbol, you should do a finger prick blood glucose test and treat based on that result.

If you are having symptoms of low or high blood sugar, you should check your blood sugar manually, because the Freestyle Libre has no alarms.


The Freestyle Libre is currently covered by Medicare for those who qualify. Download the buying guide from the Freestyle Libre website to find a list of providers.

If you're not on Medicaid, the Freestyle Libre may cost $40 to $75 per month for people covered by commercial insurance. The system is available in participating pharmacies nationwide. Talk to your care provider to find one near you.

The strips used in the meter are called Precision Neo test strips. Typically, a box of 50 costs about $20. They are individually foil-wrapped so that they can be used until the expiration date. Using other test strips with the built-in meter may produce an error or cause it to not turn on or start a test. You cannot use the meter to test for ketones.


Freestyle Libre is the first CGM that eliminates fingersticks for calibration. Instead of checking fingersticks multiple times per day, persons with diabetes can scan their CGM (a painless procedure) to get real-time glucose readings that they can use for insulin dosing, meal planning, etc.

For those people who loathe testing, this could help them to better manage their diabetes, all while improving their quality of life. In addition, large amounts of data and trend reports can help people with diabetes reduce their risk for low blood sugar and help them to figure out insulin dosing and meal planning.

For those people with diabetes who could not afford other CGMs, the Medicare-covered Libre System may provide them with a solution.

Comparing to Other Devices

The Libre device is referred to as a flash glucose monitoring system. As compared to other CGMs, like the Dexcom G4 and G5, the Libre system checks glucose every minute rather than every five minutes and it can be worn for 14 days as opposed to seven. It is very accurate and does not require fingerstick calibrations. Because the Libre does not require a transmitter, the price for it and its sensors is lower compared to other CGMs.

Additionally, sensor placement is not approved for sites other than the back of the arm (other CGMs are approved for belly and buttocks placement). If placed in other areas, the sensor may not function properly.

Another difference is that Libre does not have any automatic alarms—potentially to avoid alarm fatigue. You can still detect a high or low blood sugar, but only after scanning your device. If at that time you've identified an abnormal blood sugar, the reader will alert you and prompt you to set a reminder to scan again.


Storage is important to protect the sensor and keep the glucose readings as accurate as possible. Avoid freezing the sensor kit and only store the kit between 39 degrees Fahrenheit (3.8 degrees Celsius) and 77 degrees Fahrenheit (25 degrees Celsius). You don’t need to keep your sensor kit in a refrigerator, but you can as long as the refrigerator is between those temperatures Store the sensor kit between 10 to 90 percent non-condensing humidity.


One of the biggest limitations is that there are no alarms without a sensor scan. The Libre System will not automatically alert you if your blood sugar is very high or very low unless you scan your sensor. For example, the System will not alert you if your blood sugar is low when you are sleeping.

The Libre has not been evaluated for use in people with hypoglycemia unawareness, nor for anyone less than 18 years of age.

A Word From Verywell

The Freestyle Libre Glucose Monitoring System is the first CGM to eliminate finger stick calibration. This is exciting news for people with diabetes.

One major difference to consider before discussing this with your physician is that the Libre System does not have built-in alarms and is not meant for patients younger than 18 years of age. Eligible patients with diabetes must receive a prescription to get this meter. If you think you are eligible and are interested, ask your healthcare team about it. If you have any doubts, you can always see if you can trial the Freestyle Libre before getting started.

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Article Sources
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  1. Blum A. Freestyle Libre Glucose Monitoring System. Clin Diabetes. 2018;36(2):203-204. doi:10.2337/cd17-0130

  2. Abbott. FreeStyle Libre 14 Day Indications and Important Safety Information. Verified September 2018.

  3. Abbott. FreeStyle Libre - Medicare Guide. Last Updated March 29, 2018.

Additional Reading
  • Abbott. Indications and Important Safety Information.

  • American Diabetes Association. Standards of Medical Care in Diabetes – 2017. Diabetes Care. 2017 Jan; 38 (Suppl 1): S1-132.