Abstract
The problems to be investigated in setting up a competitive protein-binding (CPB) assay have been considered: the choice of plasma protein, tissue protein or antibody as the assay protein; the separation of bound and unbound fractions; sample preparation with respect to the removal or destruction of interfering binding-proteins and the separation of competing analogues. Factors giving rise to blank values have been discussed as well as problems encountered in running CPB assays routinely.