The OECD has published a new Guideline on Defined Approaches for Skin Sensitisation (OECD GL No. 497). This is a new type of OECD Guideline that uses several types of combined information to provide chemical safety information and can replace the need for animal test data. The project to develop this new Guideline started in 2017 and was led by the United States, the European Commission Joint Research Centre and Health Canada, supported by a group of nominated experts. The Defined Approaches (DAs) were validated using an extensively curated large set of human and mouse reference data on skin sensitisation. A supporting document providing details on the data curation and performance characteristics of the DAs on skin sensitisation will be published soon in the OECD Series on Testing and Assessment

A Defined Approach (DA) consists of selected information sources (e.g. in silico predictions, in chemicoin vitro data) used in a specific combination, and resulting data are interpreted using a fixed data interpretation procedure (DIP) (e.g. a mathematical, rule-based model). DAs are intended to overcome some limitations of the individual methods. 

The first three DAs included in this Guideline use combinations of OECD validated in chemico and in vitro test data, in some cases along with in silico information.  The DAs included in this Guideline have shown to either provide the same level of information or be more informative than the LLNA (OECD TG 429) for hazard identification (i.e. sensitiser versus non-sensitiser).  In addition, two of the DAs provide information for sensitisation potency categorisation that is equivalent to the potency categorisation information provided by the LLNA.

 This new Guideline is intended to be the first of more harmonised defined approaches adopted across OECD member countries and countries adhering to the Mutual Acceptance of Data system to 1) address regulatory needs, 2) enhance the utility of individual methods when used in testing strategies, and 3) reduce use of animal testing.


Further new test guidelines and updates include:

Section 4

Test No. 498: In vitro Phototoxicity - Reconstructed Human Epidermis Phototoxicity test method

Test No. 250: EASZY assay - Detection of Endocrine Active Substances, acting through estrogen receptors, using transgenic tg(cyp19a1b:GFP) Zebrafish embrYos

Test No. 494: Vitrigel-Eye Irritancy Test Method for Identifying Chemicals Not Requiring Classification and Labelling for Eye Irritation or Serious Eye Damage

Test No. 455: Performance-Based Test Guideline for Stably Transfected Transactivation In Vitro Assays to Detect Estrogen Receptor Agonists and Antagonists
Test No. 439: In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method

Test No. 442C: In Chemico Skin Sensitisation

Test No. 405: Acute Eye Irritation/Corrosion

Test No. 406: Skin Sensitisation


Section 2

Test No. 249: Fish Cell Line Acute Toxicity - The RTgill-W1 cell line assay

Test No. 211: Daphnia magna Reproduction Test