Types of Toxicological Tests

Acute Toxicity Measure Acute toxicity of a chemical may be measured through different routes and by systemic exposures by injections such as subcutaneous, intravenous, intramuscular, and intratracheal, which are all used in experimental and medical support. Appropriate knowledge about measures and acute toxicity warnings of chemicals are necessary to contain chemical hazards vis-a-vis to achieve chemical safety and human health. 

LC50 is the measure of toxicity through the inhalation route. LC means lethal concentration, where the amount of inhaled chemical is indicated. The LC50 values are measured in milligrams per liter of air. Again, the lower the LC50 value, the more severe the toxicity of the chemical. 

The parameters of the study include clinical examination (hematology, clinical biochemistry) of the animals in test and control groups, gross necropsy of all animals of the study, and complete histopathology of all organs and tissues.87,95 

TABLE 2-10 Exposure Period in a Repeated-Dose and Subchronic Toxicity Study 

Dominant lethal Transmissable (nontransmissable genetic alteration alteration) 

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The critical factors for deciding between approaches have little or nothing to do with the types of toxicological test systems that should be applied. The only way a test procedure would affect these decisions is if it places such demands on the quantity of sample required that the approach becomes cost-ineffective. Consequently, the assumption is made that the testing done will be approximately the same regardless of the approach taken. 

The circumstances surrounding the case will usually determine the types of toxicological tests that are required. There are different screens specific for the type of substance... 

The types of toxicological tests and test conditions required... 

For toxicological tests requiring nonrodents, researchers choose species in which the organ systems of interest closely resemble those of humans. While the number of animals required also varies with each drug according to statistical principles (516a), table 6-1 shows the usual number for each type of toxicological test. 

C) Where appropriate, identification of toxicologic testing needed to identify the types or levels of exposure that may present significant risk of adverse healtii effects in humans. 

The types of scientific tests needed to estabhsh safety are dependent on the nature of the regulated product and its proposed use. A product such as a food or color additive will require tests to elucidate the potential of the product to induce adverse acute, subchronic, and chronic effects. The safety tests are generally performed in animals and other biological systems. Both the t5rpes of tests and the methodology of particular tests have changed over the years with scientific advances in the field of toxicology. 

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