METHOD FOR DETECTING ERRONEOUS MEASUREMENT RESULTS OBTAINED WITH ION SELECTIVE ELECTRODES

A method for measuring the concentration of at least two analytes in a biological liquid sample by means of a set of ion selective electrodes each of which is suitable for measuring one of those analytes, one of those analytes being sodium and another of those analytes being potassium. The method comprises the following steps: (a) measuring and storing a series of different biological samples of the same kind with said set of ion selective electrodes, obtaining from the ion selective electrodes voltage values in millivolt representative of the concentration of sodium and potassium respectively in those biological samples, (b) measuring and storing a calibration standard for sodium and potassium with the respective ion selective electrodes after measuring each of said biological samples according to step (a), obtaining from the ion selective electrodes voltage values in millivolt representative of the concentration of sodium and potassium respectively in those calibration standards, (c) verifying by a predetermined procedure whether each of said values in millivolt obtained by measuring said calibration standards according to step (b) has an abnormal value caused by a disturbance of the measurement conditions in one of the ion selective electrodes, and if this is the case (d) markingwith a flag as doubtful the measurement results obtained for the corresponding sample which was measured before measuring the calibration standards for sodium and potassium according to step (b).