Sensors & Transmitters

Calibrating Your Sensor

What It Is

Your CGM system requires blood glucose (BG) meter readings in order to generate sensor glucose readings. These BG meter readings are entered into the pump/monitor and are used for calibrations. Calibrations are essential to making sure the glucose sensor maintains its accuracy over time. Continuous Glucose Monitoring (CGM) does not eliminate the need for BG meter readings.

How to Calibrate

Important: Calibration is important for sensor performance. Calibrating 3-4 times per day can optimize sensor performance.

To calibrate, you must use a fingerstick blood sample to test your blood glucose (BG) on your meter and then enter that value into your pump. The pump will accept BG meter readings between 40 mg/dL to 400 mg/dL. And the minimum number of calibrations required is once every 12 hours (after the first day), but calibrating three to four times a day can optimize sensor accuracy.

When calibrating your sensors, remember to:

  • Wash your hands before taking a fingerstick test.
  • Enter the BG (blood glucose) readings into the pump/monitor right away.
  • Don’t use old meter BG readings or previous sensor readings as a calibration.
  • Wait at least 15 minutes between calibration entries.

 

Ways to Calibrate How To

Automatically

For MiniMed® 530G (551/751), Revel™ (523/723)

If you use a linking meter, when you test your BG with a fingerstick, the value will be automatically sent from the meter to your device.


For 522/722 and Guardian

When using the glucose sensor on one of these models, turn OFF the automatic linking feature. Use one of the manual options listed to enter glucose values from your BG meter.

Manually

For MiniMed 530G (551/751), Revel (523/723)

MAIN MENU > Sensor > Calibrate > ENTER BG


For 522/722 and Guardian

MAIN MENU > SENSOR > Enter Meter BG

Manually with the Bolus Wizard Feature (Not available on Guardian)

1. Press B Description: C:\Users\kingen1\Desktop\Website\Image\B Image.png Button

2. ENTER BG > BG to update Sensor: YES

Tips for Calibrating a Sensor

Remembering to calibrate your sensor can be simple. Try setting up a calibration schedule based on your daily routine and normal activities so that the calibrations are both convenient and optimal for sensor performance.

You can even set a "Cal Reminder" in the pump/monitor to make sure you don't forget! Click here to learn how to set this reminder.

IMPORTANT: Make sure to enter your BG reading into the pump/monitor right away. Delaying the calibration entry could impact the sensor’s performance since your glucose levels may have changed within that time period.

Here are some other things to CONSIDER when calibrating a CGM system, as they may impact your sensor's performance:

  • If you notice a large difference between BG and sensor glucose (SG) when it's time for a scheduled calibration, do not use the BG value for calibration.
  • You don't need to use every BG reading as a calibration, only when it's needed.
  • Never re-use old BG values to re-calibrate. Always take a new fingerstick measurement when calibrating your sensor.
  • Don't calibrate when you receive alerts like Sensor Error or Weak Signal

Remember: Your sensor will not update immediately. It may take around 15 minutes for your sensor to update with a new calibration.

Best Times to Calibrate the Enlite Sensor

Calibrate three to four times spread out throughout the day.

  • You can calibrate anytime during any rate of change. However, calibrating with two down arrows may decrease accuracy until the next calibration.
  • Before bedtime
  • Before insulin
  • Enter your meter BG reading into the pump immediately after testing your BG. Do not wait to enter it later.

Did You Know: You do not need to wait until you are alerted to calibrate. Time your calibrations so you will not have to wake up in the middle of the night. For example, if it’s 9 p.m. and you know a calibration will be required by 3 a.m., go ahead and calibrate before bed. This will start the 12 hour calibration clock over.

Best Times to Calibrate the Sof-sensor

The best times to calibrate are when glucose levels are least likely to be changing rapidly. Think Before:

  • Before meals
  • Before bedtime
  • Before insulin
  • When there are no arrows on your insulin pump screen

Did You Know: You do not need to wait until you are alerted to calibrate. You can calibrate at any time when your glucose is stable. Time your calibrations so you will not have to wake up in the middle of the night. For example, if it’s 9 p.m. and you know a calibration will be required by 3 a.m., go ahead and calibrate before bed. This will start the 12 hour calibration clock over.

Why Sensor Readings are Different from BG Readings

Important: Always rely on BG meter readings for therapy adjustments.

Your blood glucose (BG) meter measures glucose levels in your blood, and your glucose sensor measures glucose levels in the fluid surrounding the cells in your tissue, which is called 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 normal and should be expected.

Important: Focus on what matters: the direction and the speed of the sensor glucose change. Pay less attention to each individual glucose number and more attention to the trends.

Usually your BG meter readings and your sensor readings will be close. However, when glucose levels are rising or falling quickly, you should expect to see a larger difference between your BG meter value and the sensor glucose reading. Examples of times when this may occur include:

  • After meals or after bolus insulin
  • When UP or DOWN arrows appear on your device screen

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