Quantitative aspects of the E2 receptor assay for human breast tumour cytosol using dextran-coated charcoal

Misclassification of the oestrogen status of a human breast tumour cytosol, arising from different sources and magnitudes of error in the dextran-coated charcoal (DCC) method, have been investigated using both practical and computer simulated data analysed by Scatchard and Mass Action models. The minimum detectable receptor site concentration, relative or absolute numerical bias and imprecision which are complex and integral functions of misclassification, have been calculated from practical data and for a range of experimental conditions likely to be encountered in practice. The Mass Action model was found to be superior and the computer program, designed to investigate the effects of methodological errors on quantitative aspects of the assay, may be a useful aid for analytical design and internal quality control of the receptor assay.