Bioassay is a shorthand commonly used term for biological assay and is a type of in vitro experiment. Bioassays are typically conducted to measure the effects of a substance on a living organism. Bioassays may be qualitative or quantitative, the latter often involving an estimation of the concentration or potency of a substance by measurement of the biological response that it produces. Quantitative bioassays are typically analyzed using the methods of biostatistics. Bioassays are essential in the development of new drugs.

The use of bioassays include:

1. measurement of the pharmacological activity of new or chemically undefined substances
2. investigation of the function of endogenous mediators
3. determination of the side-effect profile, including the degree of drug toxicity
4. measurement of the concentration of known substances (alternatives to the use of whole animals have made this use obsolete)

See also

• Drug discovery
• Pharmacodynamics
• Pharmacokinetics

Pharmacology