High Throughput Assays & Tox21

In 2007, the National Research Council (NRC) released a report, “Toxicity Testing in the 21st Century: A Vision and a Strategy” calling for a modern approach to toxicity testing that relies on in vitro methods as opposed to traditional animal testing. This initiative involves the development and use of high-throughput screening (HTS), which allows for the simultaneous testing of many samples under different conditions, often using HTS robots to automate the process. This approach generates concentration-response curves for thousands of screened chemical and aims to identify potential mechanistic targets of chemicals that may cause adverse health effects in humans in a more rapid and efficient manner than traditional toxicological studies.

Tox21 is the organized and collaborative effort that has been underway since 2008 to meet these aims. Specifically, government agencies including the NIEHS/NTP, NCGC, EPA, and FDA have been tasked with identifying, characterizing, and elucidating toxicity pathways using innovative testing methods for thousands of chemicals. These agencies have partnered to utilize HTS and have deposited data from tested chemicals into public databases. The results of HTS assays are also used in pharmaceutical drug discovery. Proper utilization of the new and expanding toxicological data from these efforts requires careful consideration and interpretation.

Exponent’s Expertise in Toxicology Testing

Exponent scientists have been instrumental in this revolution in toxicity testing, serving on the 2007 NRC panel responsible for release of the groundbreaking Tox21 report and participating in other related committee and workshop activities through the NRC, National Academy of Sciences and EPA. We have been involved in leading government agencies in the implementation of HTS assays for toxicity testing.

Our toxicologists have the technical expertise necessary to assist our clients in interpreting of results from such HTS assays, in evaluating whether these assays may replace more traditional animal toxicity testing methods or can provide relevant information regarding mode of action, and in determining if the findings from such assays may be used in assessing potential health risks for humans.