A biokinetic model describes the time course of absorption, distribution, metabolism and excretion of material or radiation introduced into the body of an organism.

An assay is an analytic test to detect the presence, measure the concentration, and determine the biological activity of molecule, ions, or cells. Assays are based on measurable parameters that enable the evaluation of differences between samples and controls. Sensitivity, the ability to detect small amounts of a substance, and specificity, the ability to detect only the analyte, are essential features of an assay.

See also Bioassay, Biochemical, Biohazards, Biokinetic Model and Bioaccumulation Factor.