1.1 Main purposes The main purpose of this International Standard is to formally represent the content and hierarchical structure of healthcare classification systems in a markup language for the safe exchange and distribution of data and structure between organizations and dissimilar software products. The scope of healthcare classifications systems covered in this International Standard encompasses terminologies, and is constrained to traditional paper-based systems (like ICD-10) and systems built according to categorial structures and a cross thesaurus (like ICNP). (2) This International Standard is intended for representation of healthcare classification systems in which classes have textual definitions, hierarchical ordering, named hierarchical levels (such as chapter , section ), inclusion- and exclusion criteria, and codes. It is not intended to cover any formal representation, either for definition or composition, of concepts, or for specification of classification rules. Systems with such formal specifications can at best be partially represented using this International Standard, and are hence out of scope. The reader of this document will recognize that most of the notes and examples in this standard relate to ICD-10. This is due to the fact that that ICD-10 is the most common classification system in the scope of this standard. As a highly complex classification system it is an inexhaustible source for examples of nearly any kind. But all these notes and examples represent also any other similar classification systems, if applicable, which are usually less complex. An overview of currently known classification systems using ClaML is provided in a separate document attached to the standard in the section resources. 1.2 Topics considered outside the scope of this International standard This International Standard is not intended to: a)provide a normative syntax on how a healthcare classification system is to be constructed; b)define link types between elements in a healthcare classification system; this is left to thedevelopers of healthcare classification systems; c)provide a representation for direct viewing or printing.