This part of ISO 21549 is applicable to situations in which clinical data additional to the limited clinical data defined in ISO 21549-3 is recorded on or transported by patient healthcare data cards compliant with the physical dimensions of ID-1 cards defined by ISO/IEC 7810.This part of ISO 21549 specifies the basic structure of the data contained within the data object extended clinical data, but does not specify or mandate particular data sets for storage on devices.In order to facilitate interoperability, whenever an application is built for use in the healthcare domain in compliance with this part of ISO 21549, data items required for that application are drawn from the list of objects (some of which are extensible) as provided in Clause 5. These are used in conjunction with other data defined in other parts of this International Standard.The detailed functions and mechanisms of the following services are not within the scope of this part of ISO 21549, (although its structures can accommodate suitable data objects elsewhere specified).— The encoding of free text data.— Security functions and related services which are likely to be specified by users for data cards depending on their specific application, for example: confidentiality protection, data integrity protection, and authentication of persons and devices related to these functions.— Access control services which may depend on active use of some data card classes such as microprocessor cards.— The initialisation and issuing process (which begins the operating lifetime of an individual data card, and by which the data card is prepared for the data to be subsequently communicated to it according to this part of ISO 21549).