1. The accuracy of the sensors (Flash vs Enlite glucose monitoring) will be evaluated with a standardized breakfast test. Patients receive a standardized breakfast. The usual insulin bolus will be administered at breakfast. After breakfast, a venous blood sample is taken for 2 hours every 15 minutes to determine the blood sugar. At the same time, the glucose value shown by the sensors will be noted. A comparison of the blood glucose value with the data recorded by the sensor can evaluate the accuracy of the sensor and also estimate the lag-time between the sensor glucose and the venous glucose.