TABLE 2.

Comparison of key experimental steps and technical components of the OECD TG442E GARDskin method and the GARDskin Medical Device protocols.

Experimental step/technical component	TG 442E GARDskin	GARDskin medical device
Cellular test system	SenzaCell cell line (ATCC Depository PTA-123875)	SenzaCell cell line (ATCC Depository PTA-123875)
Test itema	Pure monoconstituent chemical	Test material extract
Vehicles/extraction vehicles a	DMSO, dH2O (Final in-well concentration 0.1%)	Olive oil, Sesame oil, saline (Final in-well concentration 10%)
Default top concentration for cytotoxicity screening1	500 μM (pure test item concentration)	10% (test material extract concentration)
GARDskin input concentration	Rv90-concentration or default top concentration. Identical in all replicate samples	Rv90-concentration or default top concentration. Allowed to vary across replicate samples
Positive control	PPD, administered in accepted vehicle	PPD, administered in accepted vehicle
Negative control	Blank vehicle at in-well concentration	Blank vehicle at in-well concentration
Endpoint measurement	Quantified gene expression of the GARDskin GPS	Quantified gene expression of the GARDskin GPS
Analysis pipeline	Default GARDskin analysis pipeline b	Default GARDskin analysis pipeline b
Prediction model1	Mean DV ≥ 0: sensitizer	Mean DV in any one vehicle ≥0: sensitizer

^a Notable difference.

^b For details, cf OECD, 2022a.