Health Level Seven or HL7 is a range of global standards for the transfer of clinical and administrative health data between applications. The HL7 standards focus on the application layer, which is “layer 7” in the Open Systems Interconnection model. The standards are produced by Health Level Seven International, an international standards organization, and are adopted by other standards issuing bodies such as American National Standards Institute and International Organization for Standardization. There are a range of primary standards that are commonly used across the industry, as well as secondary standards which are less frequently adopted.

Health organizations typically have many different computer systems used to process different patient administration or clinical tasks, such as billing, medication management, patient tracking, and documentation. All of these systems should communicate, or “interface”, with each other when they receive new information or when they wish to retrieve information. HL7 International specifies a number of flexible standards, guidelines, and methodologies by which these healthcare systems can communicate with each other. The standards allow for easier ‘interoperability’ of healthcare data as it is shared and processed uniformly and consistently by the different systems. This allows clinical and non-clinical data to be shared more easily, theoretically improving patient care and health system performance.