A device for determining blood glucose characteristics, comprising: - a detector input (1) that can receive a signal from a detector (5), the signal based on a blood glucose value detected from a user, - a memory (3), configured to store a plurality of measurements of the second blood glucose value detected from the user from a signal received from the detector, - a screen (4), configured to present a graphical representation of the plurality of measurements of the characteristic blood glucose value, and - a controller (2), configured to control the presentation of the graphic representation on the screen, in which the controller (2) is further configured to perform a time analysis to determine a time measurement for a first measurement that provides a first detected blood glucose value assigned to a first range of detected blood glucose values and a last measurement that provides a second value of blood glucose detected assigned to a second range of values of blood glucose detected. wherein the graphic representation comprises a trend indicator (22) indicating an approximate trend of values in the blood glucose value detected over a recent series of the plurality of measurements, in which the trend indicator (22) comprises a plurality of graphic segments (23, 24), each of the graphic segments (23, 24) being of different graphic style and assigned to a different range of blood glucose values detected, thereby indicating a transition from the first range of blood glucose values detected at the second range of blood glucose values detected, and characterized in that the controller (2) is further configured to - prevent the graphical representation of the trend indicator (22) on the screen (4) if from the analysis in time one of the following conditions is concluded: - a time interval between the first and the last measurement is shorter than an interval the minimum time, and - the time interval between the first and the last measurement is longer than a maximum time i
