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Where Should the CGM Sensor be Positioned

The Libre sensor is designed to be worn on the back of the upper arm only. Placing it elsewhere may cause inaccurate readings or discomfort.

Choosing the right spot

  • Select a flat area on the back of your upper arm that stays flat during normal activity (no bending or folding)

  • Aim for the soft, fatty area between the muscles. Inserting directly over a muscle can cause discomfort

  • Avoid scars, moles, stretch marks, and lumps

  • Keep the sensor at least 1 inch (2.5 cm) away from any insulin injection site

  • Alternate arms with each new sensor to give your skin time to recover and reduce irritation

How to prepare your skin

Proper skin prep is the most important step for keeping your sensor on for the full 15-day wear period:

  1. Wash the area with plain, non-moisturizing, fragrance-free soap and water

  2. Dry the area completely with a clean towel

  3. Clean with an alcohol wipe to remove any oily residue

  4. Let air dry completely before applying (this is critical for adhesion)

Tip: If you have hair at the application site, consider shaving it beforehand. Avoid applying lotions, sunscreen, or moisturizer to the area before application.

How to apply the sensor

  1. Unscrew the cap from the sensor applicator (do not put the cap back on, as it may damage the sensor)

  2. Place the applicator over the prepared area on the back of your upper arm

  3. Press down firmly until you hear the click

  4. Wait a few seconds, then pull the applicator away slowly

  5. Gently press around the edge of the sensor with two fingers to secure adhesion

The needle does not stay in your arm. A small filament sits just under the skin to measure glucose in your interstitial fluid.

Keeping the sensor in place

  • Wear lightweight, loose-fitting clothing around the sensor

  • Be mindful of doorways, car doors, seatbelts, and backpack straps that could catch the sensor

  • If you need extra hold, consider using an over-bandage (like Tegaderm I.V.) applied at the time of sensor application. Do not cover the center opening of the sensor

Video guide

For a visual walkthrough, watch Abbott's official guide: How to Set Up Your Libre Sensor

When to replace

After 15 days, your sensor should be removed. Pull up the adhesive edge and slowly peel it off in a single motion. Apply your new sensor to a different spot on the back of your upper arm.

Need Help?

Our team is always happy to assist. Reach us at [email protected] or through our in-app messenger.

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