ADRA is an alternative method developed based on the principle of covalent bonding between sensitizer and proteins in the early stage of the mechanism of skin sensitization. The Direct Peptide Reactivity Assay (DPRA) with same principle previously listed in the OECD test guidelines and uses a seven-amino acid peptide containing cysteine or lysine as a nucleophilic reagent. Therefore, DPRA’s detection sensitivity in measurement by HPLC-UV is not sufficient, so it is necessary to prepare a high-concentration test chemical. Therefore, there are problems such as precipitation of the test chemical in the reaction solution and co-elution of the peptide and the test chemical. While, instead of DPRA, the ADRA was developed using two chemically synthesized nucleophilic reagents-namely, N‐(2‐(1‐naphthyl)acetyl)‐L‐cysteine (NAC) and α‐N‐(2‐(1‐naphthyl)acetyl)‐L‐lysine (NAL)-in which naphthalene rings with a high molar absorbance coefficient in the ultraviolet range have been introduced to N‐termini of the cysteine and lysine amino acids that react with the test chemical. Therefore, in March 2016, we set up a validation team consisting of JaCVAM, universities, chemical companies, and domestic and foreign experts with the aim for listing in the OECD guidelines. First, experimental technology was transferred to participating facilities, troubles that occurred at each facility were shared, and the protocol was improved so that highly reproducible results could be obtained at any facility, and then validation tests were conducted. After preparing a validation report, a third-party evaluation meeting and two commenting rounds, ADRA was able to be included in the OECD Test Guidelines in June 2019. In addition, since the introduction of naphthalene which has a high obsorption has made it possible to reduce the concentration, enabling the following items. (1) Decrease in the frequency of precipitation of the test chemicals in the reaction solution (2) Decrease in the frequency of co-eluting of the nucleating reagent and the chemical (3) It is possible to evaluate chemicals with unknown molecular weight using the gravimetric approach (4) High-sensitivity detection of nucleophilic reagents by the fluorescence method (5) Evaluation the mixture by a combination of the gravimetric approach and fluorescence detection (6) Evaluation for photo-allergy chemicals, (7) Evaluation of respiratory sensitizing chemicals. Since ADRA is in chemico method, there is no need to prepare animals or cultured cells, and not only can it be evaluated easily, but it can also be implemented with 96-well microplates, so high throughput system is possible. Therefore, it is considered that it can be applied to drug toxicity screening, and it is expected that it will be used in the pharmaceutical field in the future.