Sometimes your CGM may be calibrated slightly higher or slightly lower than true value. Both the CGM device and the finger prick devices are allowed by the FDA to have up to a 15% variation from what you would receive from a full lab draw at a physicians office. The most important thing to consider is the overall trends rather than an exact number. For example, how much you increased after eating and how soon you return to pre-meal values. The change in glucose is very precise and reflects real changes.
To adjust for this, we offer a manual calibration feature within the app under Settings > Sensor > Manual Calibration. You can adjust the CGM graph in comparison to a recent fasting glucose value from a lab or a fasting glucose value taken from a glucometer at home. Let's say you take a fasting glucometer value and it says 90, but the CGM fasting value says 110. You can make the baseline adjustment "-20" and refresh the app and the whole graph will be shifted 20 points down.
We recommend only making adjustments to the graph in comparison to fasting glucose values when your glucose is stable. We also recommend avoiding calibrating the sensor until after the first 24 hours of wearing the CGM.