HPPT App

Web Application to Classify and Subcategorize Skin Sensitizers Using Human Data

Access the HPPT App Tool

Download HPPT App template file for use in the tool

NICEATM has developed the HPPT App to facilitate easy application of a modified GHS classification approach for classifying skin sensitization potency that considers human data. The HPPT App has an interactive platform for users to input data, visualize results, and understand classification outputs. The HPPT App also provides a user guide and background information.

Background on the HPPT App

NICEATM and collaborators at the German Federal Institute for Risk Assessment (BfR) developed an approach that uses data from human predictive patch test (HPPT) assays to consider skin sensitization potency in assigning chemicals to subcategories of the GHS hazard classification system (Herzler et al. 2024).

While the modified classification approach is clearly useful, it is challenging for some users to understand and implement. NICEATM developed the HPPT App to address this barrier to use.

• This approach uses data on both the number of sensitized human test subjects and the dose required to sensitize a human test subject. It provides an approach to potency classification that is potentially more human-relevant than the current classification approach.
• If the data are not able to support a definitive classification, the approach provides ambiguous classifications that can indicate either that there is no evidence for the chemical being a strong sensitizer or that the data provided are insufficient to support any classification.
• The approach includes a weight-of-evidence method to consolidate multiple HPPT results into a single GHS classification for each chemical.

A user guide and additional background information are available in the app. An overview of the app is provided in a poster (Unnikrishnan, To, et al.) presented at the 13th World Congress on Alternatives and Animal Use in the Life Sciences.