TESTING HOMOGENEITY OF INTRA-RUN VARIANCE PARAMETERS IN IMMUNOASSAY

A common assumption in the analysis of immunoassay data is a similar p attern of within-run variation across runs of the assay. One makes thi s assumption without formal investigation of its validity, despite the widely acknowledged fact that accurate understanding of intra-run var iation is critical to reliable calibration inference. We propose a sim ple procedure for a. formal test of the assumption of the homogeneity of parameters that characterize intra-run variation based on represent ation of standard curve data from multiple assay runs by a non-linear mixed effects model. We examine the performance of the procedure and i nvestigate the robustness of calibration inference to incorrect assump tions about the pattern of intra-run variation. (C) 1997 by John Wiley & Sons, Ltd.