Continuous glucose monitoring and sensors
What is a glucose sensor?
A glucose sensor is a tiny electrode that measures your glucose levels. It sits under the skin in your interstitial fluid, where cells get oxygen and nutrients, including glucose. Glucose sensors are easily inserted using an automatic insertion device: like many types of infusion sets, a needle is used to insert the glucose sensor. The needle is then removed leaving just the tiny flexible electrode under the skin. The glucose sensor is then connected either to a transmitter so that readings can be transmitted to your insulin pump or monitor, or a recorder for downloading to software once removed.
Do I still need to do fingerstick readings if I use glucose sensors?
Using glucose sensors does not replace the need for fingerstick measurements. You still need to use your blood glucose meter to confirm a continuous glucose monitoring (CGM) reading before treating and to calibrate the CGM system.
What are the highest and lowest glucose alarm thresholds that I can set?
High alarm thresholds can be set as high as 22.2 mmol/L and the minimum low alarm threshold can be set as low as 2.2 mmol/L.
High and low threshold ranges can be customized by the user. You should discuss your personal threshold levels and alert settings with your healthcare provider.
The high and low glucose alarms have to be at least 0.6 mmol/L apart.
For example, if you set your high glucose limit at 10 mmol/L, then you cannot set your low glucose limit greater than 9.4 mmol/L. Conversely, if you set your low glucose limit at 2.8 mmol/L then you cannot set your high limit lower than 3.4 mmol/L.
How long do glucose sensors last? Do they expire?
Each glucose sensor can be worn for up to 6 days at a time. Glucose sensors have a 6 month expiration date from the time they are manufactured. The expiration date is on the outside of the glucose sensor box and on each individual glucose sensor package.
What type of batteries does the transmitter use?
The transmitter has a self-contained battery, which can be recharged using the charger supplied, but cannot be changed. As it has a self-contained battery, the transmitter should be disposed of, or recycled, in accordance with local governing ordinances and recycling guidelines.
What is the warranty of the transmitter?
The MiniLink™ transmitter has a 1 year warranty from date of purchase.
Do I need to refrigerate my glucose sensors?
Our Enlite glucose sensors do not need to be refrigerated. Enlite™ glucose sensor can be stored at temperatures ranging between 2˚ and 30˚Celsius (36˚ to 86˚ Fahrenheit) without the need for cooling. To identify these glucose sensors, look for a temperature graphic on the outside of the individual glucose sensor package, or on the side of the glucose sensor box.
Our glucose sensors have been comprehensively tested to safely withstand extreme hot and cold weather shipping conditions in the “non-refrigerated” shipping boxes.
Glucose sensors must not be frozen.
If you choose to keep your sensors in the refrigerator anyway, allow approximately 15 minutes for the sensor to warm up to room temperature before you use it.
Where should I wear a glucose sensor?
Where you wear your glucose sensor may be influenced by clothing, comfort, individual preference or experience. You may want to avoid recent infusion sites. The Enlite sensor is approved for wear on the abdomen or buttock. While many people choose the abdominal area, some people prefer the upper buttocks, as this location is less likely to be bumped or affected by clothing at the waistline.
See the Enlite User guide for recommended locations of insertion.
On the insulin pump, how will I know when the transmitter battery is getting low?
When the transmitter reaches a low battery condition, it will notify the insulin pump. The pump will display a "Low battery transmitter" notification. The battery in the transmitter needs to be recharged within 24 hours. Recharge your transmitter as soon as possible.
When the transmitter reaches a low battery condition, it will notify the insulin pump or monitor. It will display a "LOW TRANSMTR" notification. From the first "LOW TRANSMTR" notification of a low battery, you have about 5 days of continuous use before the battery is completely depleted. You will then receive a "BAD TRANSMTR" notice which means the transmitter battery has been depleted.
See the Alerts & Alarms section for more information.
What is the operating range between the transmitter and the insulin pump?
The transmitter and the insulin pump must be within approximately 2 metres (6 feet) of each other for wireless transmission to occur.
What happens when the transmitter and insulin pump move out of range?
If the transmitter and insulin pump are too far apart (about 2 meters or 6 feet), an alert will sound and either a "LOST SENSOR SIGNAL” or “SENSOR SIGNAL NOT FOUND" message will appear on the screen.
The transmitter holds 10 hours of data. If the transmitter and insulin pump are too far apart for longer than 10 hours, reports may have a "data gap" where information is missing during this time period.
If the transmitter and insulin pump are too far apart (more than 2 metres or 6 feet), an alert will sound and either a "WEAK SIGNAL" or "LOST SENSOR" message will appear on the screen. The MiniMed® REAL-Time insulin pump and continuous glucose monitoring (CGM) system allows to set the period of time the insulin pump will wait before alerting you of a failed reception of CGM data from the transmitter to the insulin pump. The delay can be set between 5 and 40 minutes. The default setting is 30 minutes.
The transmitter holds 40 minutes’ worth of memory; if the transmitter and insulin pump are too far apart for longer than 40 minutes, reports will have a "data gap" where information is missing during this time period.
Is the radio frequency from my transmitter harmful to me in any way?
The Guardian Link transmitter uses about 1,000 times less radio frequency (RF) power than a mobile phone. When talking on a mobile phone, you are receiving a constant stream of RF transmission. In contrast, our transmitter sends very small transmission “bursts,” which are not harmful.
The MiniLink™ transmitter sends very small transmission “bursts” which are not harmful*.
*Data on file.
How do you turn off the transmission from the transmitter to the insulin pump?
The Guardian Link begins transmitting data as soon as it is connected with the glucose sensor. The transmitter also transmits data when the CGM on the insulin pump is off. Therefore, you should disconnect the glucose sensor from the transmitter. The glucose sensor can remain inserted.
The transmitter begins transmitting data as soon as it is connected with the glucose sensor. It also transmits data when the CGM on the insulin pump is off. Therefore, you should disconnect the glucose sensor from the transmitter. The glucose sensor can remain inserted.
Why do I have to calibrate?
Calibrating your system is like setting the time on your watch and adjusting it occasionally to make sure it’s still showing the correct time. To initialize a glucose sensor, you need to enter a meter reading to give the system a starting point. You will then need to enter at least 2 meter readings a day – once every 12 hours. This aligns the glucose sensor with the meter so that CGM readings are representative of your blood glucose (BG) level.
How often do I have to calibrate the insulin pump?
Calibration is only necessary when you are using the CGM function of your insulin pump. The MiniMed 630G insulin pump must be calibrated a minimum of twice a day (once every 12 hours) by entering a meter BG value into the insulin pump. Follow these guidelines for best calibration results:
Spread out your calibrations throughout the day. To optimize sensor accuracy, calibrate 3 to 4 times a day.
Although you can calibrate any time during any rate of change, calibrating with 2-3 up or down arrows may temporarily decrease accuracy until the next calibration.
Enter your BG meter reading into the pump immediately after testing your BG.
Your BG meter reading is only valid for 12 minutes; do not wait to enter it later.
Always use clean, dry fingers when you test your BG levels.
Use only your fingertips when obtaining blood samples for calibration.
If your BG meter readings are significantly different than your sensor glucose readings, you need to wash your hands and calibrate again.
Calibration is only necessary when you are using the CGM function of your insulin pump. The MiniMed® Veo™ insulin pump must be calibrated a minimum of twice a day (once every 12 hours) by entering a fingerstick value into the insulin pump. However, for best results, you can calibrate 3 to 4 times per day, with the calibrations spread throughout the day at periods when glucose is not changing rapidly. This will allow more accurate glucose detection at all levels.
When should I calibrate the insulin pump?
The following table describes when you should calibrate your sensor.
When it is: You need to
Two hours after starting a new sensor. Do your first sensor calibration.
Two hours after you start your new sensor, your pump sends a “Calibrate Now” alert.
Your first sensor glucose reading appears about 10 to 15 minutes after you calibrate.
Within six hours of your first calibration. Do your second sensor calibration.
Within six hours of calibrating for the 1st time, a “Calibrate Now” alert appears, and your
pump stops calculating your sensor glucose (SG) values.
When you receive a “Calibrate Now” alert, it takes about 15 minutes after you calibrate to receive SG values again
Twelve hours after your second
Calibration, and then at least
every 12 hours thereafter.
After you do your 2nd calibration, you need to calibrate at least every 12 hours.
If you do not calibrate for more than 12 hours, a “Calibrate Now” alert appears.
It takes about 15 minutes after you calibrate to receive SG values again.
Follow these guidelines for best calibration results:
- Spread out your calibrations throughout the day. To optimize sensor accuracy, calibrate 3 to 4 times a day.
- Although you can calibrate any time during any rate of change, calibrating with 2-3 up or down arrows may temporarily decrease accuracy until the next calibration.
- Enter your BG meter reading into the pump immediately after testing your BG.
- Your BG meter reading is only valid for 12 minutes; do not wait to enter it later.
- Always use clean, dry fingers when you test your blood glucose levels.
- Use only your fingertips when obtaining blood samples for calibration.
- If your BG meter readings are significantly different than your sensor glucose readings, you need to wash your hands and calibrate again.
For support on the CONTOUR® NEXT LINK 2.4 blood glucose meter please visit:
It is best to calibrate when your blood glucose is not changing rapidly. We recommend that you calibrate on a routine schedule, for instance when you first wake up, before a meal, or before your bedtime snack. Try to find a time during the day when your blood sugar is stable as it is important to calibrate when glucose values are not changing rapidly. For example, glucose is more stable before a meal; do not calibrate after a meal, because it is more likely that glucose will change rapidly to adjust for the food being digested.
Visit myLearning online product modules for more information at www.medtronicdiabetes.ca/mylearning
The CGM readings do not match my meter readings. Should I be concerned about this?
BG meters take glucose readings from plasma blood whereas sensors take readings from interstitial fluid. Most of the time glucose travels first to your blood and then to your interstitial fluid. Because of how glucose travels your BG meter readings and sensor glucose readings will rarely match exactly. This is quite normal.