Bioassays are typically conducted to measure the effects of a substance on a living organism. Bioassays may be qualitative or quantitative. Qualitative bioassays are used for assessing the physical effects of a substance that may not be quantified, such as abnormal development or deformity. An example of a qualitative bioassay includes Arnold Adolph Berthold's famous experiment on castrated chickens. This analysis found that by removing the testes of a chicken, it would not develop into a rooster because the endocrine signals necessary for this process weren't available. Quantitative bioassays involve 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.
The use of bioassays include:
Bioassays are essential in the development of new drugs, and monitoring pollutants in the environment. Environmental bioassays are generally a broad-range survey of toxicity, and a toxicity identification evaluation is conducted to determine what the relevant toxicants are. Although bioassays are beneficial in determining the biological activity within an organism, they can often be time-consuming, laborious, and organism-specific factors may result in data that isn't applicable to others in that species. For these reasons, other biological techniques are often employed, including radioimmunoassays.