Interstitial fluid glucose measurements are taken from the fluid within tissue while blood glucose measurements are taken directly from the blood. Sensor glucose values, which are based on interstitial fluid glucose levels, can be different from blood glucose levels (fingersticks*), particularly during times when your blood glucose is changing quickly. For example after eating, taking insulin, or exercising. When glucose levels are falling quickly, glucose readings from the sensor may be higher than blood glucose levels. On the other hand, when glucose levels are rising quickly, glucose readings from the sensor may be lower than blood glucose levels.
* Fingersticks are required for treatment decisions when you see Check Blood Glucose symbol, when symptoms do not match system readings, when you suspect readings may be inaccurate, or when you experience symptoms that may be due to high or low blood glucose.