FreeStyle Libre 3 is a continuous glucose monitoring (CGM) system that you wear on your skin. It's designed to replace fingersticks for people ages 4 years and older with diabetes. It measures your glucose level every minute throughout the day to better help you manage your blood sugar. The FreeStyle Libre 3 system uses a sensor that's attached to your skin, which can be scanned and read using an app on a smart device (e.g., smartphone). It doesn't include a reader, and it's important to check phone compatibility to make sure the FreeStyle Libre 3 app will work properly.
Monitor glucose levels
The FreeStyle Libre 3 system is made up of two parts that work together to measure and record your glucose levels throughout the day.
Sensor: The sensor is attached to the skin on the back of your upper arm to measure your glucose levels from just below the skin.
FreeStyle Libre 3 app: The app on your smart device displays and stores the readings.
Lessens the need for fingersticks
Sensors only about the size of two stacked pennies
Stores up to 14 days of glucose level data
Displays glucose level every minute on your smart device
Only works with an app on a compatible smart device
Intense exercise can make your sensor loose
Sensor must be stored between 36 F and 82 F to work properly
Must wait 60 minutes after placing a new sensor to check glucose
How to set up your FreeStyle Libre 3:
The FreeStyle Libre 3 system only works with an app on a smart device (e.g., your smartphone). Download the FreeStyle Libre 3 app to pair with your sensor and see your glucose readings.
When you're ready to insert your FreeStyle Libre 3 sensor, first wash and dry your hands. Choose the place on the back of your upper arm where you want to insert the sensor and wipe the area with an alcohol wipe. Then, unscrew the cap from the sensor applicator and push down firmly against your skin to apply the sensor.
Gently pull the applicator away from your body. Make sure the sensor is secure. Watch this video to learn more about applying your sensor.
If you just applied a new sensor, follow the instructions on your FreeStyle Libre 3 app to scan your sensor and activate it for use.
Each time you apply a new FreeStyle Libre 3 sensor, you'll need to wait 1 hour before you can check your glucose readings with the FreeStyle Libre 3 app on your smart device.
To check your glucose reading, open the FreeStyle Libre 3 app or go to the app home screen.
How to remove FreeStyle Libre 3 sensors:
You'll need to replace your FreeStyle Libre 3 sensor once every 14 days, or sooner if it becomes loose.
To remove the sensor, find the edge of the adhesive on your sensor and pull up on it. Then, slowly peel the sensor off your skin.
When applying a new sensor, choose a place on the back of your upper arm that's different from the most recent position. This will help prevent skin irritation.
Screw the used applicator and lid back together and throw it away in a sharps container or yellow biohazard bag. Your used sensors can be wiped down with disinfectant and thrown away as electrical waste, like a battery.
FreeStyle Libre 3 can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
You must remove FreeStyle Libre 3 before getting a magnetic
resonance imaging (MRI), computed tomography (CT) scan, or high-frequency electrical heat (diathermy) treatment. These medical tests might damage the sensor and cause incorrect glucose readings. If you're scheduled for any medical tests or imaging, let your provider know that you're using FreeStyle Libre 3.
If you're going through security, such as at the airport, let the security personnel know that you're wearing a CGM. Don't go through (or put any part of the FreeStyle Libre 3 system through) any body scanners or X-ray machines. Instead, request that they use another method for screening. It isn't known how X-rays or other scanners affect FreeStyle Libre 3, and they could damage the sensor and affect its performance.
If you have symptoms of low or high blood sugar and they aren't matching up with your FreeStyle Libre 3 readings, always do a fingerstick blood sugar test and contact your provider. Make sure to have a separate blood glucose monitor at home, since the app doesn't provide one.
FreeStyle Libre 3 has optional alarms that must be turned on in the app if you want to use them. In order for you to get alarms, your phone must be within 33 feet of you at all times. Make sure that the Bluetooth setting on your smart device is turned on. Keep your device charged and turned on.
Taking vitamin C (ascorbic acid) can affect the accuracy of the glucose readings from FreeStyle Libre 3. If you take more than 500 mg of vitamin C while wearing the sensor, your glucose readings might be falsely high. This can raise your risk for dangerously low blood sugar levels. Before taking any supplements, check how much vitamin C they contain. Vitamin C is commonly found in multivitamins and cold remedies. If you're not sure, ask your pharmacist for help.
The FreeStyle Libre 3 sensors have an adhesive that keeps them attached to your skin. If you notice redness, swelling, or a lot of irritation around or under your sensor, remove the sensor and contact your healthcare provider.
The FreeStyle Libre 3 sensors are only meant for single use. Don't reuse or share them with anyone else. If you reuse them, you might get inaccurate glucose readings. Reusing or sharing sensors raises the risk of infection. If your sensor becomes loose, remove it and apply a new sensor.
People ages 4 years and older: Place a new FreeStyle Libre 3 sensor on the skin of the back of the upper arm once every 14 days.
Use with automated insulin dosing (AID) systems
Getting magnetic resonance imaging (MRI), computed tomography (CT) scan, or high-frequency electrical heat (diathermy) treatment at the same time
Age 3 years or younger
Currently pregnant
Currently on dialysis
Currently seriously ill
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Heinemann, L., et al. (2020). Benefits and limitations of MARD as a performance parameter for continuous glucose monitoring in the interstitial space. Journal of Diabetes Science and Technology.
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