What is FreeStyle Libre 3 Plus Sensor: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Oct 29, 2024

FreeStyle Libre 3 Plus is a prescription continuous tissue glucose monitoring system for people with diabetes. Sensor readings are sent to a smartphone app, reader, or insulin pump to help people control blood sugar levels throughout the day. Sensors are replaced every 15 days.

FreeStyle Libre 3 Plus Sensor overview

BRAND NAMES:

  • FreeStyle Libre 3 Plus

Generic Names:

  • Continuous interstitial glucose monitoring system

Uses:

  • Continuously monitors tissue glucose levels in people with diabetes.

Therapeutic Classes:

  • Medical device

Forms:

  • Wearable sensor

How it’s taken:

  • Worn on the skin

What is FreeStyle Libre 3 Plus Sensor used for?

The Abbott FreeStyle Libre 3 Plus CGM system continuously monitors tissue glucose levels in people with Type 1 or Type 2 diabetes. The system can be used by adults and children 2 years of age and older.

What form(s) does FreeStyle Libre 3 Plus Sensor come in

  • Replaceable skin sensors

What are common FreeStyle Libre 3 Plus Sensor doses?

  • For continuous glucose monitoring: Replace the FreeStyle Libre 3 Plus sensor every 15 days

How to take FreeStyle Libre 3 Plus Sensor

  • How to set up the FreeStyle Libre 3 app:

    • Download the FreeStyle Libre 3 app to your smartphone.

    • Disable automatic operating system updates on the smartphone.

    • Always keep the smartphone’s Bluetooth turned on.

    • Open the app and set up the alarms in the app.

    • Do not force close the app on the phone.

    • Keep the phone charged.

  • Any headphones or speakers should be detached from the phone if they’re not being used.

  • Keep the phone within 33 feet of the sensor at all times.

  • The sensor can also be used with the FreeStyle Libre 3 reader. 

  • How to place a sensor:

    • Read the Sensor Application Guide and Adhesion Guide first.

    • Do not use the sensor if it has been damaged or passed its expiration date. 

    • Sensors should always be placed on the flat part of the back of the arm.

    • Choose a place that is at least one inch away from the nearest insulin injection site.

    • Wash the application site with a non-moisturizing, fragrance-free soap.

    • If there’s hair, consider shaving the site.

    • Wipe the skin with an alcohol swab.

    • Let the skin completely dry before applying the sensor.

    • Remove the sensor applicator cap. Set it aside.

    • Press the applicator firmly against the skin on the back of the arm.

    • Listen for a click. Wait a few seconds.

    • Slowly pull the applicator away.

    • Make sure the sensor is firmly attached.

    • Place the cap back on the applicator.

    • Follow the pharmacist’s instructions when disposing of the applicator.

  • After a sensor is in place:

    • Connect the sensor to the app or the reader. You can only connect the sensor to one or the other, not both.

    • Scan the sensor with either the smartphone app or reader following the instructions in the User Guide or Quick Start Guide.

    • Check the sensor by taking a reading on the smartphone app or reader.

    • You can check glucose readings 60 minutes after the sensor has been scanned. You will receive a notification on the smartphone when it’s ready.

    • Check the accuracy of the sensor’s readings for the next 12 hours by taking regular fingerstick tests.

    • The sensor can only operate in a temperature range between 50°F and 114°F.

    • The sensor can be immersed in water up to three feet deep for up to 30 minutes. 

  • How to connect the sensor with an insulin pump:

    • The FreeStyle Libre 3 Plus system only works with the Beta Bionics iLet Bionic Pancreas automated insulin delivery pump. It is not compatible with any other insulin pump.

    • Install the current iLet app on your smartphone. 

    • Pair the app with the iLet insulin pump. 

    • Once the app and the pump are paired, use the app to update the firmware on the pump. 

    • To link the iLet app to the CGM system, click “Switch CGM Sensor” on the iLet CGM menu. 

    • On the “Switch CGM Sensor” screen, change the CGM sensor type to “Abbott Libre 3 Plus.”

    • Go to the Settings/CGM screen.

    • Click “Start Sensor” on the Settings/CGM screen in order to scan the new sensor and link it to the pump.

  • 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 that come with these products.

    • Be careful not to dislodge the sensor. Gently put on clothing. Wear loose-fitting clothing. Avoid hitting or brushing objects with the sensor arm. 

    • Above all, don’t fidget, poke, or play with the sensor.

    • After showering, bathing, or swimming, pat rather than rub the area dry.

    • When washing the arm, pat but don’t rub with a washcloth. 

    • Exercise or heavy sweating can loosen the sensor.

    • Do not try to re-apply a sensor that is coming loose.

  • How to replace a sensor:

    • Replace a sensor after 15 days or the app will indicate that it needs replacement. 

    • A sensor also needs replacement if it’s coming loose or if you can see the tip. 

    • Do not reuse sensors.

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

    • Carefully peel it from the skin.

    • You can use products that help remove the sensor such as baby oil or adhesive dissolvers.

    • Carefully remove the tip from the skin.

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

    • Choose a different location to attach the new sensor. 

    • Follow the instructions for applying a new sensor.

  • How to store unused sensors:

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

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

    • If the temperature gets too hot, store the sensors in the refrigerator.

    • Protect unused sensors from extreme humidity (higher than 90%).

What to do if you miss a dose of FreeStyle Libre 3 Plus Sensor

  • If a sensor hasn’t been replaced on time, do it as soon as possible. 

  • Use another method to measure glucose levels until the new sensor is in place.

FreeStyle Libre 3 Plus Sensor contraindications

  • FreeStyle Libre 3 sensors should not be used by:

    • Critically ill patients

    • People on dialysis

  • To avoid sensor damage, it must be removed before any MRI scan, CT scan, or high-frequency electrical heat treatment (diathermy). 

FreeStyle Libre 3 Plus Sensor warnings

  • Before first using FreeStyle Libre sensors, tell the prescriber if you:

  • Are pregnant

  • On dialysis

  • Have another implanted medical device.

  • Tell all healthcare providers who treat you that you are wearing a FreeStyle Libre 3 Plus sensor.

  • The FreeStyle Libre 3 Plus sensor will not provide dependable readings in people who:

    • Are dehydrated

    • In shock

    • Have low blood pressure (hypotension)

    • Have dangerously high blood sugar levels (hyperglycemic-hyperosmolar state)

  • Drink plenty of fluids to stay hydrated. Dehydration and water loss can give inaccurate readings. 

  • FreeStyle Libre 3 sensor readings are not always accurate. You must perform a fingerstick blood test when:

    • The sensor is first placed and for 12 hours after it has warmed up

    • The smartphone app or reader displays a Check Blood Glucose symbol

    • The sensor reading has no number

    • You experience symptoms of high or low blood sugar

    • Sensor readings don’t match the way you feel

    • You think the readings may not be correct

  • Do not share the app with any other person. 

  • Allergic reactions are a common side effect of wearing FreeStyle sensors. Remove the sensor and contact the prescriber if you experience skin reactions or irritation around or beneath the sensor. 

FreeStyle Libre 3 Plus Sensor interactions

  • FreeStyle Libre 3 Plus is a medical device that does not have drug interactions.

  • However, some medications, supplements, and personal care products can make sensor readings inaccurate, particularly:

    • High-dose vitamin C (> 500 mg daily) 

    • Aspirin

    • Some skin care products

  • Tell all doctors and other healthcare providers treating you that you are wearing a continuous glucose monitoring system before they prescribe any new medications.

FreeStyle Libre 3 Plus Sensor side effects

When used as instructed, FreeStyle Libre 3 Plus sensors, reader, and app do not cause serious side effects. The most common side effects are skin reactions to the sensors:

  • Skin redness

  • Bleeding

  • Bruising

  • Scab formation

Subscribe to our savings newsletter

Health education, drug info, wellness & more

By clicking 'Subscribe', I agree to SingleCare's Terms & Conditions.