An assay's a procedure in molecular biology for testing and/or measuring the activity of a drug or biochemical in an organism or organic sample. A quantitative assay may also measure the amount of a substance in a sample. Bioassays and immunoassays are among the many varieties of specialized biochemical assays. Other assays measure such processes as enzyme activity, antigen capture, stem cell activity, and competitive protein binding. Assay varieties Cytotoxicity A cytotoxicity assay measures h… (More on Assaying)