Canadian Medical Guide > Analytical, Diagnostic and Therapeutic Techniques and Equipment > Investigative Techniques > Toxicity Tests Terms and Definitions

Toxicity Tests

Medical Definition:	An array of tests used to determine the toxicity of a substance to living systems. These include tests on clinical drugs, foods, and environmental pollutants.
Guide Notes:	GEN or unspecified; prefer specifics; used for tests of drugs, food, environ pollutants, etc.; when the test itself is emphasized; coord IM with substance /tox (IM); toxic eff of a specific substance = specific substance /tox; DF: TOX TESTS
Previously Indexed:	Toxicology/methods (1975-1994),specific substance/toxicity (1966-1994)

Toxicity Tests Categories.

	Acute Toxicity Tests - Experiments designed to determine the potential toxic effects of one-time, short-term exposure to a chemical or chemicals.
	Carcinogenicity Tests - Tests to experimentally measure the tumor-producing/cancer cell-producing potency of an agent by administering the agent (e.g., benzanthracenes) and observing the quantity of tumors or the cell transformation developed over a given period of time. The carcinogenicity value is usually measured as milligrams of agent administered per tumor developed. Though this test differs from the DNA-repair and bacterial microsome MUTAGENICITY TESTS, researchers often attempt to correlate the finding of carcinogenicity values and mutagenicity values.
	Inhibitory Concentration 50 - The concentration of a compound needed to reduce population growth of organisms, including eukaryotic cells, by 50% in vitro. Though often expressed to denote in vitro antibacterial activity, it is also used as a benchmark for cytotoxicity to eukaryotic cells in culture.
	Lethal Dose 50 - The dose amount of poisonous or toxic substance or dose of ionizing radiation required to kill 50% of the tested population.
	Maximum Tolerated Dose - The highest dose of a biologically active agent given during a chronic study that will not reduce longevity from effects other than carcinogenicity. (from Lewis Dictionary of Toxicology, 1st ed)
	No-Observed-Adverse-Effect Level - The highest dosage administered that does not produce toxic effects. The NOAEL will depend on how closely dosages are spaced (lowest-observed-adverse-effect level and no-observed-effect level) and the number of animals examined. The ultimate objective is usually to determine not the "safe" dosage in laboratory animals but the "safe" dosage for humans. Therefore, the extrapolation most often required of toxicologists is from high-dosage studies in laboratory animals to low doses in humans. (Casarett and Doull's Toxicology: The Basic Science of Poisons, 4th ed)
	Toxicity Tests, Chronic - Experiments designed to determine the potential toxic effects of a long-term exposure to a chemical or chemicals.

Toxicity Tests Medical Definitions and Terms

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