Skin irritation testing
OECD TG 439
For this test 3D human reconstructed skin models are exposed to the test material for 1 hour. Afterwards models are rinsed and incubated for 24 hours. At the next day supernatant can be collected for analysis of cytokines (e.g. IL-1α, optionally). Subsequently vitality is assessed by MTT-test (colorimetric assay). If remaining vitality is > 50 % the test material is non-irritant.
|Mean tissue viability
(expressed as % of negative control)
|in vivo Prediction|
|EPI-200-SIT||OECD TG No. 439
(adopted and updated 2019)
|< 50 %||Irritant (I)
(R38 or GHS category 2)
|requiring classification and labelling (GHS Category 1 or 2)|
|> 50 %||non-irritant (NI)||non-irritant to skin (GHS no category, no labelling requirements)|
The Modified EpiDerm™ SIT allows discrimination between irritants of category 2 and non-irritants. The test does not discriminate between non-mandatory subcategories of the UN GHS, i.e. it does not distinguish between GHS category 2 and category 3 irritants.