What is Freestyle Libre: Uses, Warnings & Interactions

Download the appropriate Freestyle Libre app to a smartphone.

• Open the app and set up the alarms.

• Keep Bluetooth on.

• Keep the phone charged.

• Do not close the app.

• Remove headphones or speakers from the phone when not in use.

• Keep the phone within 20 feet (FreeStyle Libre 2) or 33 feet (FreeStyle Libre 3) of the sensor at all times.

The sensor can also be used with an appropriate FreeStyle Libre, FreeStyle Libre 2, or FreeStyle Libre 3 reader. 

Read the Sensor Application and Adhesion Guide before placing the sensor on the skin.

How to place a sensor:

• Do not use sensors that appear damaged or have passed their expiration date.

• The sensor should be placed on the flat part of the back of the arm.

• Wash the skin with non-moisturizing, fragrance-free soap.

• Wipe the skin with an alcohol swab to remove skin oils.

• Completely dry the skin.

• You will use an applicator to apply the sensor.

• If you are using the FreeStyle Libre 3 system, you must first remove the sensor applicator cap.

• Make sure the sensor pack codes and the sensor applicator codes match.

• Never touch the inside of the applicator. It contains a needle.

• Put the sensor pack on a hard, flat surface.

• Line up the mark on the applicator with the mark on the sensor pack.

• Press the applicator firmly down onto the sensor pack until you can’t push anymore.

• With the sensor in place, press the applicator firmly against the skin on the back of the arm. The applicator should click.

• Hold it there for a few seconds.

• Slowly pull off the applicator.

After a sensor is in place:

• Take a reading to check the sensor using the smartphone app or appropriate monitor.

• The FreeStyle Libre 2 or FreeStyle Libre 3 sensor will automatically update the app if it is in range.

• The Freestyle Libre sensor can only be scanned by placing the phone near the sensor. The “scan” button must be pressed on the iPhone app. This is not necessary on the Android app.

• In the first 12 hours of wearing a new sensor, take regular blood sugar fingerstick tests to determine the sensor's accuracy.

• The sensor may not give accurate readings if it’s exposed to temperatures below 39°F or temperatures above 77°F (FreeStyle Libre) or 82°F (Freestyle Libre 2 or 3)

Keeping a sensor in place:

• To help keep the sensor in place, you can use a bandage, medical-grade tape, Tegaderm I.V., Torbot Skin-Tac, Mastisol Liquid Adhesive, or Skin-Prep Protective Barrier Wipes. Follow the instructions for these products.

• Don’t fidget or fiddle with the sensor. Just leave it alone.

• Be careful when using the arm with the sensor. Don’t hit or brush objects that could pull it off, and dress carefully to avoid pulling it off.

• Wear loose-fitting clothing.

• After showering, bathing, or swimming, pat the area dry. Do not rub it with a towel or washcloth.

• Exercise or heavy sweating can loosen the sensor.

How to replace a sensor:

• FreeStyle Libre, FreeStyle Libre 2, and Freestyle Libre 3 sensors must be replaced after 14 days.

• FreeStyle Libre 2 Plus and FreeStyle Libre 3 Plus sensors must be replaced after 15 days.

• Replace a sensor if it’s coming loose or the app tells you to replace it.

• Do not reuse sensors.

• To remove a sensor, pull up the adhesive edge.

• Carefully pull it off the skin.

• You can use moisturizing products to remove the sensor.

• Choose a different location on the back of an arm to place the new sensor.

• Ask the pharmacist how to dispose of the sensor. Disposal laws vary by location.

How to store unused sensors:

• Store unused FreeStyle Libre sensors at room temperature between 39°F and 77°F.

• Store unused FreeStyle Libre 2 and FreeStyle Libre 3 sensors at room temperature between 39°F and 82°F. 

• The sensors may not work properly if exposed to temperatures outside this range.

How to purchase FreeStyle Libre 2 Plus for use with an insulin pump:

• The FreeStyle Libre 2 Plus and FreeStyle Libre 3 Plus sensors can work with the Tandem t: slim X2 insulin pump with Control-IQ technology. It is not compatible with any other insulin pump.

• FreeStyle Libre 2 Plus sensors cannot be purchased at pharmacies. They can only be purchased at select distributors.

If you have forgotten to replace a sensor, do it when remembered. 

If you don’t have a sensor, use another method to measure glucose levels.

The FreeStyle Libre sensor must be removed before any MRI scan, CT scan, or any high-frequency electrical heat treatment (diathermy). The scan or treatment may damage the sensor.

The FreeStyle Libre 2 and Freestyle Libre 3 sensors must be removed before any high-frequency electrical heat treatment. 

FreeStyle Libre, FreeStyle Libre 2, and FreeStyle Libre 3 are not intended for use by:

• Critically ill patients

• People on dialysis

• Pregnant women (FreeStyle Libre only)

Tell all doctors and other healthcare providers treating you that you are wearing a FreeStyle Libre sensor.

Before getting a prescription, tell the prescribing healthcare provider if you are pregnant, on dialysis, or have any other implanted medical device.

The sensor will not provide accurate readings in people with the following conditions:

• Dehydration

• Low blood pressure

• Shock

• Hyperglycemic-hyperosmolar state

Sensor readings must be periodically checked with a fingerstick test when:

• The app displays a Check Blood Glucose symbol

• You have symptoms of low or high blood sugar

• You experience symptoms that do not match the reading

• You need to confirm blood sugar levels

• Glucose levels are rapidly changing

• Sensor readings are doubtful or suspicious

• Sensor readings do not include a Current Glucose or Glucose Trend Arrow 

Dehydration and water loss can give inaccurate readings. Drink plenty of fluids to stay hydrated, and when dehydrated, talk to a healthcare professional.

Only FreeStyle Libre 2 and FreeStyle Libre 3 sensors have real-time alarms, which can be used to wake you while you sleep. 

The FreeStyle Libre alarms will not work unless the sensor is scanned, and they will not wake you when you’re sleeping.

To avoid confusion, do not share the app with any other person.

When removing and disposing of the sensor, take all necessary precautions to avoid spreading infection.

The sensor can cause allergic reactions. If you notice skin reactions or irritation beneath or around the sensor, remove the sensor and contact the prescriber.

FreeStyle Libre does not interact with medications, but other medications can affect the sensor’s accuracy. Tell all doctors and other healthcare providers treating you that you are wearing a continuous glucose monitoring system before they prescribe any medications.

Some common foods or medications can alter sensor readings, particularly:

• Vitamin C (especially 500 mg or 1000 mg doses)

• Aspirin

• Some skin care products