Computer implemented method for determining a normalized concentration or activity of an analyte in a sample, including a respective confidence information, the method comprising: a) determining one or more measurement values representative of the concentration or activity of the analyte from the sample, b) determining one or more measurement values representative of the concentration or activity of at least two reference substances from said and/or other samples, c) obtaining an estimation by using an estimator of true values and respective confidence information for said estimate for the concentration or activity of the analyte and the at least two reference substances from the measurements in a) and b), d) obtaining an estimation by using an estimator of a normalized value and respective confidence information for said estimate representative of the concentration or activity of the analyte from values in a), b) and c), wherein the normalized value and respective confidence information is bounded from below, above or both, wherein the confidence information from d) is used to determine a quality control criterion for said determination of the concentration or activity of the analyte, wherein the measurement values a) and b) are one of: - a numeric value related to the concentration or activity or the target or reference, respectively, - the value "Undetected" related to a very small concentration or activity, in particular below the LOD, - the value "Invalid" denoting that a severe problem occurred during measurement and this measurement or replicate should be ignored, and wherein step c) of claim 1 is realized by a noise model wherein either - the true value is modeled as a normal distribution with mean equal to the measured value and a standard deviation calculated from a parameterized function, where parameters were fitted based on training data, or - the measured value is modeled as a normal distribution with mean equal to the true value and a standard deviation calculated from a parameterized function, where parameters were fitted based on training data. e) outputting the estimated values obtained at steps c) and d). a) determining one or more measurement values representative of the concentration or activity of the analyte from the sample, b) determining one or more measurement values representative of the concentration or activity of at least two reference substances from said and/or other samples, c) obtaining an estimation by using an estimator of true values and respective confidence information for said estimate for the concentration or activity of the analyte and the at least two reference substances from the measurements in a) and b), d) obtaining an estimation by using an estimator of a normalized value and respective confidence information for said estimate representative of the concentration or activity of the analyte from values in a), b) and c), wherein the normalized value and respective confidence information is bounded from below, above or both, wherein the confidence information from d) is used to determine a quality control criterion for said determination of the concentration or activity of the analyte, wherein the measurement values a) and b) are one of: - a numeric value related to the concentration or activity or the target or reference, respectively, - the value "Undetected" related to a very small concentration or activity, in particular below the LOD, - the value "Invalid" denoting that a severe problem occurred during measurement and this measurement or replicate should be ignored, and wherein step c) of claim 1 is realized by a noise model wherein either - the true value is modeled as a normal distribution with mean equal to the measured value and a standard deviation calculated from a parameterized function, where parameters were fitted based on training data, or - the measured value is modeled as a normal distribution with mean equal to the true value and a standard deviation calculated from a parameterized function, where parameters were fitted based on training data. - a numeric value related to the concentration or activity or the target or reference, respectively, - the value "Undetected" related to a very small concentration or activity, in particular below the LOD, - the value "Invalid" denoting that a severe problem occurred during measurement and this measurement or replicate should be ignored, and - the true value is modeled as a normal distribution with mean equal to the measured value and a standard deviation calculated from a parameterized function, where parameters were fitted based on training data, or - the measured value is modeled as a normal distribution with mean equal to the true value and a standard deviation calculated from a parameterized function, where parameters were fitted based on training data. e) outputting the estimated values obtained at steps c) and d).