From @ErikaSalazar in this Spanish thread
The minimum level of information about taxonomic information of the specimens held in a collection could be the ones used in Colombia, through the Registro Único Nacional de Colecciones Biológicas, where taxonomic groups and subgroups held in collections are included. For example: Biological group: Aves; Biological Subgroup: mammals, aves, reptiles.
The ideal level would be that each collection reports the list of specimens they hold with the maximum level of taxonomic detail posible (e.g. genus or species level).