The Organization for Economic Cooperation and Development released their new test guidelines for skin sensitization testing using the KeratinoSens (OECD TG 442D) and Direct Peptide Reactivity Assay (DPRA) (OECD TG 442C) test methods. The KeratinoSens test method focuses on the second key event on the Adverse Outcome Pathway (AOP) leading to skin sensitization, the inflammatory response and gene expression in keratinocytes associated with the antioxidant/electrophile response element (ARE)-dependent pathways. The DPRA assay is in in chemico assay that addresses protein reactivity (a molecular initiating event leading to skin sensitization) by quantifying the reactivity of test chemicals towards synthetic peptides containing either lysine or cysteine. IIVS is pleased to have participated in the inter-laboratory study on KeratinoSens that was submitted to ECVAM and offers both the KeratinoSens and DPRA assays as part of our GLP-compliant laboratory testing services. Please contact us for information on the in vitro assays available for skin sensitization testing at IIVS.