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A Two-Tiered-Testing Decision Tree for Assays in the USEPA-EDSP Screening Battery: Using 15 years of experience to improve screening and testing for endocrine active chemicals.
Citation:
Gray, E. AND G. Ankley. A Two-Tiered-Testing Decision Tree for Assays in the USEPA-EDSP Screening Battery: Using 15 years of experience to improve screening and testing for endocrine active chemicals. Presented at EDC Workshop, RTP, NC, April 22 - 23, 2013.
Impact/Purpose:
Absract of a presentation to present update on the EDSP EDC screening battery and how the assays and battery perform, how the battery can be streamlined and how the screening information can be used to improve tier two testing for adverse effects.
Description:
In 1996 the Food Quality Protection and Safe Drinking Water Acts instructed the USEPA to determine “…whether the pesticide chemical may have an effect in humans that is similar to an effect produced by a naturally occurring estrogen or other endocrine effects;"*. In 1998 EDSTAC, an advisory committee to EPA, recommended that EPA develop a screening battery that included mammalian and non-mammalian in vivo and in vitro assays to detect chemicals for estrogen, androgen and thyroid activities (EAT). The battery was intended to detect chemicals that disrupted EAT pathways via the E and A nuclear receptors, steroid hormone synthesis or disruption on hypothalamic-pituitary-gonadal function via EAT modes of action. The last 15 years since the release of the EDSTAC Final Report was published, EPA has been developing and validating the assays for screening and, as a result, a significant data base has been using chemicals with known EDC activities. This database enables us to review assay performance and make recommendations about 1) Interpretation of assay results with unknowns, 2) Structuring the screening battery into a “Tiered-Testing Decision Tree” with two in vivo “Gatekeeper” assays and, 3) Specifically tailoring Tier 2 testing using the EDC information gained from Tier 1 screening. This presentation will discuss development of the screening battery by EDSTAC, assay development and validation, how the battery detects different EAT modes of action, the strategy for detection of positives and negatives in a Tiered-Testing Decision Tree battery with “Gatekeeper” assays, why in vitro assays cannot serve as “Gatekeepers” and how the information from the screening battery can be used to enhance Tier 2 testing on a case-by-case basis. In addition, the presentation will address some of the criticisms of the screening battery, some of which are without merit, and reiterate how critical it is for laboratories executing the assays to strictly adhere to the published test guidelines for the screening assays. * from: FQPA - PUBLIC LAW 104–170. This is an abstract of a proposed presentation and does not reflect EPA policy.