Determining hormone metabolite concentrations when enzyme immunoassay accuracy varies over time

Data for identifying clusters of samples assayed with similar enzyme immunoassay accuracy (data_for_cluster.txt), modelling the relationship between initial and remeasured metabolite concentrations in a subset of 27 samples (data_for_fit.txt), and applying the standardisation procedure using the complete data set of 138 samples (data_for_standardisation.txt).