The FreeStyle Libre 2® intermittently scanned glucose monitoring system (isCGM, commonly referred to as flash) is a device for the self-monitoring of glucose levels. Unlike traditional finger-prick devices (that measure the glucose level in the blood), FreeStyle Libre 2® measures the glucose level in the interstitial fluid, via a sensor that sits just under the skin. It updates readings every minute and stores data every 15 minutes. FreeStyle Libre 2® is licensed for adults and children above the age of 4.

The patient swipes the reader or a smartphone with the FreeStyle LibreLink App over the sensor to get a glucose reading. It can provide a near-continuous record.

With a scan over the sensor, patients can see their current glucose reading, their 8-hour glucose history and a trend arrow showing the direction and rate of change of their glucose levels. Patients can scan as often as they want, even through clothing.

The FreeStyle Libre 2® sensor is applied to the back of the upper arm with a disposable applicator. When the sensor is applied, a 5mm sterile filament is inserted just under the skin, and held in place with a small adhesive pad. The sensor lasts for up to 14 days. There is an app patients can use with their smartphone to take readings, FreeStyle libreLink App, or use a reader

The following are possible adverse effects of inserting a sensor and wearing the adhesive patch: local erythema (redness), local infection, inflammation, pain or discomfort, bleeding at the glucose sensor insertion site, bruising, itching, scarring or skin discolouration, haematoma, and adhesive irritation.

Important Information on Blood Glucose Testing with Libre®

As Libre® measures interstitial glucose, it is not a complete substitute for blood glucose testing. Blood glucose measurements are required in certain circumstances, including:

• When advised by your diabetes team
• To meet Driving and Vehicle Licensing Authority (DVLA) requirements
• When the FreeStyle Libre 2® reader results do not correspond with the user’s symptoms (e.g. patient feels hypoglycaemic but the Libre 2 reader shows a higher glucose reading)

Patients will continue to require prescriptions for blood glucose testing strips in the situations highlighted above. The expected amount will be detailed on the initiation documentation.

Note: If FreeStyle Libre 2® has been prescribed for patients who previously used a high number of test strips, it is expected that the quantity required will fall over the first few months.