Tiered screening

Gray, L.E. (1998). Tiered screening and testing strategy for xenoestrogens and antiandrogens. Toxicology Letters 103, 677-680. 

Screening First-tier screen for potential for human target organ toxicity... 

Hie greatest difficulty with test systems today is that the tests that are most economical and sensitive use cell cultures, or, if they use whole animals, animals that are phylogenetically distant from man. In contrast, tests that use the mouse in ways that are directly comparable with the presumed human experience are too expensive to use for more than a small number of chemicals. Thus, in the tiered screening system detailed in Chapter 9, the Committee recommends that mouse tests be used only when the simpler tests have not provided enough information for a decision or when the chemical in question is so important or widespread in its use that further information is deemed crucial. 

Tier 0 exposure assessments, which are commonly used for first-tier screening purposes, do not require an analysis of uncertainty on every occasion, provided they include appropriate conservative assumptions or safety factors to take account of uncertainty. 

Hierarchical (Multi-Tiered) Screening Approaches (HMTS)... 

Figure 4-8. Strategy of tiered screening. Series of screening or selection methods with decreasing throughput and increasing accuracy are combined.

A multi-tiered screening process was developed to help identify and eliminate false leads from the solid phase library screenings in our workt as shown in Figure 3.5. 

Figure 3.5 Multi-tiered screening process. The path from primary to tertiary screening focuses the final sequence that gives the best combination of purity and yield in purification...

Gurgel etalS applied the multi-tiered screening approach to a-lactalbumin (a-La), a whey protein of significance to the food industry. Eighteen sequences were identified as potential a-La binders by screening approximately 2% of a solid phase hexameric peptide... 

Wang applied the multi-tiered screening approach to SEB, a primary toxin... 

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