What is Bioassay: Definition, Methods & advantages of Bio assays

Updated on June 25, 2012

What is Bioassay? Definition & principle of bioassay

Bioassay is an assay designed to analyse any compound by use of a suitable biological system like animals, tissues, microbes etc.
Bioassay definition: It is defined as estimation or determination of concentration or potency of a physical, chemical or biological substance (agent) by means of measuring and comparing the magnitude of the response of the test with that of standard over a suitable biological system under standard set of conditions.
In bionalysis the response produced by the test compound is compared with that of standard sample the way similar to other analytical methods but here the biological system is involved in the determination.
Principle of bioassay: The bioassay compares the test sample with a same Internationally applicable standard substance. It determines the quantity of test sample required to produce an equivalent biological response to that of standard substance.
Standard samples are accepted by expert committee at international level and they represent fixed units of activity.

Why Bioassay? Advantages & Uses of bioassay

Bioassays have some different role and purpose over other assay techniques.
1. They not only help to determine the concentration but also the potency of the sample. (Potency is a term which denotes activity of the compound per molecule basis. i.e. if a compound shows better activity at minute concentration, greater is the potency, and if its activity is low at lower concentrations, lesser is the potency).
2.It is especially used to standardize drugs, vaccines, toxins or poisons, disinfectants, antiseptics etc. as these are all used over biological system in some or other form.
3. These also help determine the specificity of a compound to be used ex: Penicillin's are effective against Gram+ve but not on Gram-ve. Testing of infected patients sputum helps determine which anti-biotic be given for quick recovery.
4. Certain complex compounds like Vitamin B-12 which can't be analysed by simple assay techniques can be effectively estimated by Bioassays.
5. Sometimes the chemical composition of samples are different but have same biological activity.
5.
5. For samples where no other methods of assays are available.