Bioassay Details

Bioassay is a testing procedure used in biopharmaceutical products to detect biological hazards. The test substance is administered on the live material with several doses to measure the dose-response relation. Bioassay is a crucial testing procedure to measure the pharmacological activity of a new or chemically untested substance. It helps to identify potential side effects that can arise from the extensive usage of the product.

Bioassays help assess the environmental impact of the test substance before releasing it to the market. Bioassay can lead to a lot of errors in testing and calculations. The calculations can be false if the test tissue has lost its sensitivity. A difference in the species' age, sex, health, or weight can bring about a difference in the test readings.

Variation in laboratory conditions and a lack of standardization in procedures can create errors in bioassay tests.

Real-World Example of Bioassay

Bioassays help detect HIV antibodies caused by infection. A rapid and sensitive bioassay quantitatively detects the HIV transactivation inhibitors. Enzyme-linked immunosorbent assay (ELISA) is a quantitative analytical method used to measure the impact of various substances in the human body. Home pregnancy tests and HIV tests use ELISA to detect pregnancy and HIV antibodies, respectively.

Bioassays often help to detect biological hazards in water supplies and sewage treatment. The environmental impact of bioassays can be vital in protecting communities for many reasons.

History of Bioassay

Since the late 19th century, bioassay has been used as a testing procedure. The process detects water, air, and soil toxicity. At the time usage of small vertebrate species like rodents were used as live test organisms. Nowadays, ethical considerations have helped reduce the usage of animals for such tests.

The "Canary in the coal mine" tradition dates back to the 1900s where miners used canaries to test the presence of methane gas at mining sites. If the Canary became ill or died, the miners would leave the site. In 1915, Japanese pathologist Yamagiwa Katsusaburo and his assistant Koichi Ichikawa demonstrated the carcinogenic properties of coal tar by testing it against the ears of a rabbit.

Paul Ehrlich developed a standardized protocol for bioassay testing. His bioassay on diphtheria antitoxin was a pioneer in the field of bioassay biochemical testing.

Types of Bioassay

There are three main types of bioassays based on the test procedure and response.

  • Direct assays are bioassay tests in which standard doses and test preparations are sufficient to produce a response that technicians can measure directly.
  • Another type of bioassay is indirect bioassay. In this case, a dose corresponding to a given response is obtained from the relation for each preparation separately.
  • The third type of bioassay is a Quantal bioassay in which the response can be one of the two extremes. The responses are "all or none" responses. They are the presence or absence-based tests produced by the threshold effect.