Evidence-based tools in toxicological hazard identification

Abstract

Hazard identification depends on the gathering and evaluation of evidence. In this context it is important to differentiate between approaches based on expert opinion and ¿weight of evidence¿, and evidence-based approaches using predefined methods and criteria. In moving towards an evidence-based approach, clear guidance for decision-making, specific for each class of agent, should be developed. Quality criteria specific for each type of hazard identification tool need to be defined, with levels of quality acceptable for each. General guidelines exist, but they are not sufficient to evaluate evidence quality in a clear and transparent manner. Further specific guidelines are required to evaluate the summed evidence. In developing these guidelines it is important to consider existing guidance documents. Careful thought should be given to designing studies to produce the evidence needed. A number of evidence-based hazard identification tools were identified. These include in silico, in vitro, in vivo, and ex vivo (analysing animal or human tissue after treatment) tools. In vitro and in vivo tools themselves include classical and novel methodologies, (e.g., transcriptomics, proteomics, and metabolomics). Clinical sample data may be used for exposure assessment, metabolomics, and biomarker analysis. These may be representative of patients, the population at large (including susceptible subgroups), workers, or consumers. Market-based information sources include rapid alert systems and other ¿hot lines¿, poison centres, occupational health data, epidemiological studies, consumer protection organizations, post-marketing surveillance, and hospital data. For all such tools, the purity profile of the agent in question should also be included in the assessment. Evidence-based guidelines should take into account all of these tools, and should be able to incorporate both retrospective and prospective data, and data from susceptible (sensitive) population subgroups. Evidence-based medicine is a useful template for evidence-based approaches to toxicology, but there are differences between these two branches of science. The evaluation of the differences and commonalities should be part of the process of establishing an evidence-based toxicology.