Updates to OECD In Vitro and In Chemico Test Guidelines

Posted on June 18, 2021

The Organisation for Economic Co-operation and Development (OECD) has published several new or updated in vitro and in chemico test guidelines.

New test guidelines include the following:

  • Test 497: Defined Approaches on Skin Sensitisation. This is the first test guideline for defined approaches. It combines multiple in vitro skin sensitisation methods based on human biology and the skin sensitisation adverse outcome pathway.
  • Test 249: Fish Cell Line Acute Toxicity – the RTgill-W1 Cell Line Assay. The gill cell line cytotoxicity assay has the potential to play an important role in replacing acute fish toxicity testing through its incorporation in a weight of evidence or integrated approach to testing and assessment (IATA) for acute fish toxicity assessment.
  • Test 498: In Vitro Phototoxicity Test Method Using the Reconstructed Human Epidermis (RhE). This method combines exposure and viability assessment according to guideline 439 on In Vitro Skin Irritation (RhE test) with the irradiation procedures in guideline 432 on the In Vitro 3T3 NRU Phototoxicity Test.

Updated versions of existing test guidelines include the following:

  • Test 439: In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method. The KeraSkin method has been included.
  • Test 442C: In Chemico Skin Sensitisation Assays Addressing the Adverse Outcome Pathways Key Event on Covalent Binding to Proteins. The kinetic DPRA test method for in chemico characterisation of skin sensitisation potency of chemicals has been included.
  • Test 494: Vitrigel-Eye Irritancy Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage. The applicability domain of the assay has been updated to include certain solids and exclude certain liquids.

Furthermore, new and updated in vivo test guidelines have been published, including the following:

  • Test 406: In Vivo Skin Sensitisation. The introduction was updated to include recommendations to consider in chemico, in vitro, and other in vivo skin sensitisation tests and conduct the Guinea Pig Maximisation Test and the Buehler test only as a last resort.
  • Test 250: Detection of Endocrine Active Substances, Acting Through Estrogen Receptors, Using Transgenic cyp19a1b-GFP Zebrafish Embryos (EASZY Assay). This assay refines the use of fish in regulatory toxicity testing.