Congratulations, you have received your FreeStyle Libre Continuous Glucose Monitoring (CGM) System! The following text will walk you through how to put on your CGM and will answer some common questions.
Applying and Activating Your CGM
The CGM lasts for 14 days and allows you to monitor your glucose levels 24/7 without any blood being drawn. When you open your CGM package, you will see 2 identical kits (or one in the case of the 14 day trial). Open one kit, and you will find alcohol wipes, a bandage cover, the sensor, and an applicator. Save the second kit for when you have to replace your CGM on day 15.
IMPORTANT: Once the sensor has been applied, it can not be re-applied or adjusted. Make sure to not test the application as it can only be done once.
- First, select an application site on the back of either arm that is dry, clean, and flat (avoid scars, bumps, moles, stretch marks, etc.). We recommend choosing an area that has the most fat present.
- Wipe the application site with the provided alcohol wipe before applying the sensor. Allow the arm to dry.
- Open the lid of the sensor and unscrew the cap of the applicator. Now that both components are open, you can load the applicator. Make sure to line up the dark marker on the applicator to the dark marker on the sensor pack and push down on a hard surface until you hear a click. Pull the two items apart, and now you have the sensor ready to insert.
- Push the applicator onto the area of your arm you have chosen. You do not have to apply much pressure.
- IMPORTANT: Once the sensor is securely attached, please use the provided bandage to protect it from water and accidental damage. (We cannot replace sensors that have fallen off due to failure to use reasonable care and they cost $85 to replace.) Do not take the bandage off once you have placed it on.
Please reference this video to watch your health coach Kara applying a CGM.
Please put your CGM on Monday through Friday so our staff is available to help in case you need assistance.
At the end of the 14 days, it will be time to remove the sensor and replace it with a new one. To remove, simply pull on the sensor housing and it will peel off - just like a bandaid. When putting on the new sensor, use the arm not previously used for maximum comfort.
Even though you will start receiving glucose readings 1 hour after sensor application, the CGM is calibrating during the first 12-24 hours and readings may not be accurate during this time.
Make sure to scan your CGM at least every 8 hours to capture all of your data.
In order to activate the sensor and record your glucose readings you will have to download the NutriSense App, please see separate instructions for downloading and using the app.
When Wearing the CGM
It should be noted that the Freestyle Libre should NOT be worn during:
- Magnetic resonance imaging (MRI)
- Computed tomography (CT) scan
- High-frequency electrical heat (diathermy) treatments
Any other procedures or scans involving the area where the sensor is placed should be discussed with your primary care provider and/or specialist prior to the procedure. If you plan on traveling while wearing the sensor, please let airport security know that you are wearing the CGM sensor. They may require you to go through a different screening process.
The adhesive on the sensor may, on rare occasions, irritate the skin. If you notice any irritation, please remove the sensor and consult with your healthcare provider. Additionally, the sensor is small and may pose a risk for swallowing or choking, please keep away from children. If the sensor wire breaks inside the skin, remove with tweezers or seek the help of a medical professional. If the sensor kit seems damaged or broken, do not apply it and contact our staff immediately. Do not use the sensor for more than 14 days after activation, it will not provide any more glucose readings. After applying the sensor, you may notice some slight discomfort, but this should go away after the first day. If it does not, please follow-up with the NutriSense team.
How Does a CGM Measure Glucose?
You may notice while applying the CGM that the applicator uses a small needle. This needle is part of the applicator itself and is only used for sensor insertion. What remains in place for the 14 days is a very thin filament, less than 0.4 millimeters, which measures glucose levels beneath the skin.
This tiny filament is actually measuring interstitial fluid (ISF) glucose levels as opposed to the blood glucose (BG) levels measured by the conventional blood glucose monitoring devices. The ISF is the fluid that surrounds our cells. This fluid is present right underneath the skin layer and allows for easy and painless insertion. Measuring the ISF glucose levels is the main reason why the CGM is so practical.
The advantage of this system is that it continuously measures glucose levels versus taking “snapshots” as with traditional finger stick blood glucose meters. The sensor takes readings every 60 seconds and saves the readings every 15 minutes to display for your long term trend data.
Accuracy & Precision
ISF Glucose levels and Blood Glucose levels will usually follow each other very closely, however there are times where the two will differ. When there is a sudden change in glucose within the body, it will impact the BG levels faster than the ISF Glucose levels. When we eat food (especially food containing simple carbohydrates which are digested quickly), your blood glucose levels may spike while your ISF glucose levels may be delayed by 10 - 15 minutes on average.
There are a few additional items that may affect the accuracy of the CGM readings and should be kept in mind:
- Dehydration can affect ISF levels and sensor glucose readings - please make sure to stay adequately hydrated.
- High caffeine intake may also dry out the interstitial fluid and cause falsely elevated readings. Staying hydrated when consuming caffeine may correct any ISF-related dehydration.
- Certain supplements and over the counter products can influence the glucose readings. If you take ascorbic acid (Vitamin C) in any form, your sensor glucose readings may be falsely elevated depending on the amount and frequency of ascorbic acid you take.
- Consuming salicylic acid (aspirin) in any form can falsely decrease sensor glucose readings.
- Taking acetaminophen (Tylenol) containing products should not affect the sensor glucose readings, however, if you take larger doses of acetaminophen on a regular basis, you may notice a slight elevation in your sensor glucose readings.
Consult your pharmacist or doctor when taking any new prescription or over-the-counter medications so you are fully aware of the ingredients and contents of these medications and how they can affect your glucose readings. If you see consistent levels that you feel are not accurate or that you are concerned about, please contact one of our coaches who will be able to assist.
Swimming, Working Out, & Sauna
Your CGM is water resistant to a certain extent. You can shower with it but you should not take it deeper than 3 feet (1 meter) underwater and you should not keep it under water for more than 30 minutes at a time. It should be noted that the sensor has not been tested in seawater so it is not recommended to go into the ocean or salt water with the sensor. You can cover it with a clear water-proof band aid if you are planning on spending a lot of time in the water.
You can shower and work out with the sensor, just be cautious not to catch it on your clothes or any other materials because it can loosen the sensor, knock it out of place, or break off the filament.
Intense sweat and movement can loosen the adhesive, if participating in intense excise please make sure that you have placed the bandage over your CGM.
If you plan on traveling to areas with extreme temperatures, please note that the sensor operates in temperatures between 50 °F and 113 °F and can be stored in temperatures between 39 °F to 77 °F.
Your Data, Privacy and HIPAA Compliance
Your personal and medical information will only be utilized by our healthcare professionals and will not be displayed or shared with anyone outside of our team. Limited information may be shared with our pharmacy partner in order to provide your with the prescription CGM device.