U.S. flag

An official website of the United States government

Dot gov

The .gov means it's official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you're on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.


ICCVAM Biennial Report 2018-2019

Biennial Progress Report 2018-2019 Interagency Coordinating Committee on the Validation of Alternative Methods

Electrophilic Allergen Screening Assay Validation Study

Binding of a chemical to skin proteins is the first step in the development of allergic contact dermatitis. The electrophilic allergen screening assay is a chemical assay that measures light absorbance or a fluorescent signal in proportion to a chemical’s tendency to bind to proteins.

The electrophilic allergen screening assay, developed by scientists at NIOSH, was nominated to ICCVAM to evaluate its usefulness for identifying potential skin sensitizers. Four ICCVAM member agencies are participating in an ongoing validation study of the assay. Testing of 10 chemicals during 2018 showed that the method has sufficiently good reproducibility and accuracy rates to support further evaluation. In 2019, CPSC and NIST modified the assay to a 96-well format to increase throughput and accessibility of the assay; details of this process are described in an abstract (Gordon et al.) accepted for presentation at the Society of Toxicology 2020 annual meeting. Testing of 20 chemicals will be conducted using the 96-well assay during 2020.