Study design All the consecutive cases of allergies over a year and registered in the DIM bases of 3 healthcare establishments (the university hospital of Montpellier (CHRUM), Paris (APHP), Toulouse) will be individualized. Depending on the size of the facility, ½ to 1/10 of the cases will be included in the study. All cases will be selected anonymously. Two professional coders will encode the selected cases twice. The analysis of the data will be based on the degree of inter-encoder agreement using Cohen's Kappa coefficient. At the end of this process, we will be able to identify the correspondence between the codes recorded in the DIM database (ICD-10) and those of the new classification. In the event of discordant results, consensus will be reached by involving other coding experts from CHRUM. The economic impact of the transition from ICD-10 to ICD-11 will be approximated by estimating the average costs per ICD code used in the main diagnosis.