ADRA(Amino acid Derivative Reactivity Assay) is in chemico test method, representing an alternative (non-animal) method, for the evaluation of skin sensitization potential compounds. The kit comprises two amino acid derivates, NAC (N-(2-(1-naphthyl)acetyl)-L-cysteine) and NAL (α-N-(2-(1-naphthyl)acetyl)-L-lysine), which are composed out of a nucleophilic region and a detection molecule (naphthalene rings).