A method for operating measuring equipment for detecting an analyte in a bodily fluid by means of a continuously measuring blood glucose sensor. A calibration method is carried out for the prospective calibration of the measuring equipment. At least three calibration points are detected in the calibration method, wherein each calibration point comprises a measurement signal from the measuring equipment and a reference value of an associated reference measurement. A plurality of possible slopes are established between the calibration points. At least one robust estimation method using a formation of at least one median is used to determine a probable slope from the plurality of possible slopes. Furthermore, a measurement is carried out. During the measurement and using the probable slope, a concentration of the analyte in the bodily fluid is deduced from a measurement signal from the measuring equipment and the probable slope.
