Chronic Toxicity Tests

Chronic toxicity is defined as adverse effects that occur after repeated or continuous administration of a test sample for most of its life.

Toxic effects are generally classified as acute toxicity or chronic toxicity. Acute toxicity is generally thought of as a single, short-term exposure where effects are immediate and usually reversible. For example, excessive alcohol consumption and discomfort the next day. Chronic toxicity, on the other hand, are generally considered to be frequent exposures where the effects may be delayed (which may take years) and are often irreversible. Chronic toxicity can also result in acute exposures with long-term chronic effects. For example, the relationship between smoking and lung cancer.

Chronic toxicity results from repeated exposure to a harmful substance for part of an organism's lifespan, most of its life, or its entire lifespan. Chronic toxicity is mainly due to the progressive accumulation of damage to one or more critical target organs.

Chronic toxicity tests are defined as tests that characterize adverse effects following repeated administration of a test substance over a substantial portion of the test species' lifespan.

Determining the duration of a chronic study is based on expected human or environmental species exposure. For example, when pharmaceuticals are tested under US Food and Drug Administration (FDA) guidance, exposure time in animals is determined by the fraction of human lifespan in which the test substance is expected to be used. Similarly, when testing under the guidance of the American Environmental Protection Agency (EPA), the test duration depends on the expected environmental exposure time and the lifetime of the ecological test types.

Both carcinogenicity tests and non-cancerous toxicity tests fit the definition of chronic testing, but there are distinctive features.

During a chronic test, organisms are continuously exposed to various concentrations of test material. The tests take between 4-7 days and responses such as growth, reproduction and survival are measured. The tests are designed to cover the entire life cycle or most sensitive life stage of organisms.

Our organization also provides chronic toxicity testing services with its trained and expert staff and advanced technological equipment, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors.