Biological assay

Bioassay (commonly used shorthand for biological assay or assessment), or biological standardization is a type of scientific experiment. A bioassay involves the use of live animal or plant (in vivo) or tissue or cell (in vitro) to determine the biological activity of a substance, such as a hormone or drug. Bioassays are typically conducted to measure the effects of a substance on a living organism and are essential in the development of new drugs and in monitoring environmental pollutants. Both are procedures by which the potency or the nature of a substance is estimated by studying its effects on living matter. A bioassay can also be used to determine the concentration of a particular constitution of a mixture that may cause harmful effects on organisms or the environment.

Bioassays are procedures that can determine the concentration or purity or biological activity of a substance such as vitamin, hormone or plant growth factor by measuring the effect on an organism, tissue, cells, enzyme or receptor. Bioassays may be or . Qualitative bioassays are used for assessing the physical effects of a substance that may not be quantified, such as seeds fail to germinate or develop abnormally deformity. An example of a qualitative bioassay includes Arnold Adolph Berthold's famous experiment on castrated chickens. This analysis found that by removing the testicles of a chicken, it would not develop into a rooster because the endocrine signals necessary for this process were not available. Quantitative bioassays involve estimation of the dose-response curve, how the response changes with increasing dose. That dose-response relation allows estimation of the dose or concentration of a substance associated with a specific biological response, such as the LC50 (concentration killing 50% of the exposed organisms). Quantitative bioassays are typically analyzed using the methods of biostatistics. For more information Look up Basic and Clinical Pharmacology by Bertram G. Katzung.

"The determination of the relative strength of a substance (e.g., a drug or hormone or toxicant) by comparing its effect on a test organism with that of a standard preparation" is called bioassay.

Similarly, Bioassay is a method of developing toxicological information on organisms whose physiology is considered similar to the organisms of direct concern to a known level of toxic chemical compound in an environmentally concerned chamber.

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