As a health care professional, it is crucial to know what tools are on the market to help our patients manage their chronic diseases. Today, we’ll be discussing Abbott’s FreeStyle Libre.
Traditionally, diabetic patients have had to rely on glucometers to track their glucose, which requires multiple finger pricks a day. The FreeStyle Libre makes it easier for patients to track their glucose by just tapping their sensor to get instant results.
What is the FreeStyle Libre?
The FreeStyle Libre is a flash glucose monitoring system that detects glucose in the interstitial fluid (ISF). Recall: ISF is found between cells.
Glucose levels in the blood are similar (but not the same!) to that in the ISF unless it is changing rapidly (ex. after meals, after exercise). Because glucose enters the bloodstream first, and is then absorbed by the ISF, there can be a 5-10 minute lag with the reading.
For more information on the lag, watch this video
Data can be viewed on the glucometer, which has to be purchased separately from the sensors, or the patient can download the LibreLink app on their smart phone.
As seen on the picture below, the screen will typically show the patient’s glucose reading as well as an arrow to indicate how rapidly their glucose is rising or falling. This is especially important if the patient scans 4 mmol/L with the arrow trending downwards, indicating a hypoglycemic event. In this case, the patient must use a glucometer to check their blood glucose. The reader (or the app) also stores information, and creates graphs so that the patient can see how their glucose trends.
How is data recorded?
Flash glucose monitoring systems do not monitor glucose continuously – the data has to be “pulled.” The sensor must be scanned by the reader (glucometer or phone app) in order to receive the data. When the sensor is scanned, it automatically transmits 8 hours of data, measuring glucose levels every minute. Thus, it must be scanned at least once every 8 hours in order for it to record continuous data throughout the day. The reader stores up to 90 days of data.
The reader can capture data up to 4 cm away, and it can be scanned through clothes.
How is the sensor applied?
Clean site of application (usually the back of the upper arm) with an alcohol wipe
Peel the lid off the sensor pack and unscrew the lid from the sensor applicator
Place the sensor applicator in the open sensor pack and line up the dark lines on the sensor pack and applicator, then push down firmly
Place the sensor applicator over the application site and press down firmly to apply
For a demonstration, watch this video
NOTE: There is a needle in the applicator; however, it does retract. It acts as a guide to allow a flexible filament to stay in the arm and this is what measures the interstitial fluid.
After the Libre is set up, the patient will not be able to scan for the first hour (there will be a countdown on the screen to notify the patient when they can start scanning). In addition, the first 12 hours may provide unreliable readings.
How often do the sensors have to be replaced?
Every 14 days. The patient’s meter will remind them to replace it. To prevent skin irritation, it is best to switch arms with each sensor change.
Can patients shower, bathe, or swim with the sensor?
Yes, up to 30 minutes up to a depth of 1 metre of water.
It is generally recommended not to use it in a hot tub or in excessively hot or humid environments, as the sensor may fall off. There are products that can be purchased at a pharmacy, such as Tegaderm, to increase adherence on the skin.
What are some important counselling points I should mention to my patients?
The patient must check their blood glucose (ie. finger prick) in the following situations:
The first 12 hours after setting up the sensor
During times of rapidly changing glucose levels when interstitial fluid glucose levels may not accurately reflect blood glucose levels, such as during exercise, stress, dehydration, or illness
If the patient gets a reading of 4.0 mmol/L or below on their FreeStyle Libre, with the arrow pointing downwards. If the patient is experiencing a hypoglycemic episode, review how to manage hypoglycemia.
When symptoms do not match readings on the sensor
The FreeStyle Precision Blood Glucose Test Strips are compatible with the FreeStyle Libre reader if the patient wishes to use the same reader for both blood and ISF glucose testing.
A great resource to direct patients to when using the FreeStyle Libre for the first time is the FreeStyle Libre website itself, including videos on how to apply the sensors, information on how to use the LibreLink mobile app, and a community of patients who share their personal experiences with diabetes management.
Diabetes management can be very overwhelming, especially with the added complexity of newer technologies for older patients. However, as pharmacists, we can help make this process as stress-free as possible by properly educating our patients on how to get started.
Click here to view our FreeStyle Libre infographic!
Frequently Asked Questions. Abbott Digital Styleguide. Accessed April 29, 2021. https://www.freestyle.abbott/ca/en/products/libre/faqs.html