Pre-validation may involve multiple laboratory studies to optimize and standardize
the protocol, and develops preliminary data on reproducibility within a single
laboratory (e.g, performance criteria). Depending upon the level of refinement
required for the protocol, pre-validation can be a very time consuming stage
of the validation process.
Several different types of studies may be needed in pre-validation, including:
- Optimization studies to choose optimum conditions for the assay, refine
the protocol, and eliminate duplicative or non-sensitive endpoints.
- Special studies to resolve unknown issues related to protocol design.
- Studies that use a small number of chemicals to demonstrate that the protocol
can provide a measure of a relevant endpoint.
- Multi-chemical studies to determine relevance:
- Studies should state expectations for each chemical;
- Studies should be conducted using chemicals with specific mechanisms of action; and
- Studies should generally use 8 to 12 chemicals for in vivo screens, perhaps
more for in vitro screens, and fewer for Tier 2 studies.
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