1. Optimal Times for Calibration:

   • Avoid Calibration in the First 24 Hours: It's not recommended to perform any calibrations during the first 24 hours of using the CGM.
   • Calibrate if the Variance Exceeds 20%: Please calibrate when the variance between the blood glucose monitoring (BGM) and CGM readings is more than 20%.

   • Calibrate on an Empty Stomach:

     • Ensure you are fasting before calibrating, as food intake can affect blood glucose levels and, consequently, the accuracy of the calibration.
     • Being "on an empty stomach" is defined as before meals or in the morning when the blood glucose is above 5mmol/L. Calibration is not recommended when blood glucose is below 4.4mmol/L because the relative error of the BG meter is larger at lower glucose levels.

2. Considering Blood Glucose Trends:

   • Before calibrating, refer to the blood glucose trend arrow and the instant blood glucose value. Calibration can be performed if the glucose trend is steady, slowly rising, or falling.

   • Interpretation of the trend arrow and numbers:

     • Steady: Changing less than 0.06 mmol/L per minute.
     • Slowly Rising or Falling: Changing between 0.06 to 0.11 mmol/L per minute.

3. Number of Calibrations:

   • There are no limitations on the number of calibrations per day, but it's essential to follow the above timings and conditions to ensure accuracy.

Calibration is a crucial step in ensuring the accuracy of CGM systems. Proper calibration timing, considering blood glucose trend directions, and the frequency of calibrations are key to maintaining the accuracy of glucose monitoring. Remember, avoid calibration in the first 24 hours of CGM use, ensure fasting before calibration, and calibrate when blood glucose trends are stable to improve the CGM's accuracy.