Abstract: A method for predicting blood glucose levels, in particular, for postprandial blood glucose level prediction, the method being computer-implemented and comprising: receiving a first medical data set of a patient covering a time range, the first medical data set comprising glucose data and further other medical data of the patient, extracting a second medical data set from the first medical data set, wherein the second medical data set is a subset of the first medical data set and wherein the extracting comprises at least one of: identifying duplicates in the first medical data set and removing identified duplicates, identifying data values that lie above a predefined maximum threshold data value or identifying data values that lie below a predefined minimum threshold data value and removing data associated with the identified data values, identifying data values that differ from predetermined expected data values by more than a predetermined amount and removing data associated with the identified data values,