ABSTRACT
Toxicologists have developed an array of animal-based tests that have been used to assess the toxicity of chemicals and mixtures of chemicals during the last half century. These methods have been adopted by regulatory agencies throughout the world to provide data that are ultimately used to protect public health and to warn chemical users of potential health dangers. Validation has been defined as the process by which the reliability and relevance of an alternative method is established for a particular purpose. Reliability has been defined as establishing the reproducibility of results within and between laboratories and over time. Relevance has been defined as establishing the scientific meaningfulness and usefulness of results from an alternative method for a particular purpose. The establishment of usefulness and meaningfulness is important because hazard predictions obtained from scientifically credible alternative methods have a higher probability of being correct.
