Sharing EHRs is a significantly more complex task than banking transactions. In banking there are two basic kinds of transactions: deposit and withdrawal. In a health record there are many different types of transactions. A patient’s hospital chart contains a large number of different paper forms, including progress notes, observations, test results, and assessments. Across a state-based health care system, it is not uncommon to have more than 2000 different forms. Even in a "summary record", the record must be able to handle summary information from a large number of professions, some of which provide complex information, such as pathology or oncology.

EHR standards provide a commonly agreed framework for dealing with such a challenge. EHR standards build upon many other key standards, such as those for identification, codes, messaging and security, but also satisfy requirements that are specific to EHRs including:

• Safe medico-legal record keeping practices, such as versioning, attestation and auditing;
• A consistent framework for structuring content in the record, so that diverse multidisciplinary content can be easily searched and compared;
• A rich set of data types for simple data, such as identifiers, codes from codes sets, quantities and unstructured text, and complex data, such as time series data and multimedia types;

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