HL7 Standard
The purpose of the Health Level Seven (HL7) standard is to facilitate communication in health care environments. The primary goal is to provide standards for the exchange of data among health care computer applications that eliminate or substantially reduce the custom interface programming and program maintenance that may otherwise be required. You can delineate this primary goal as a set of goals:
That the standard supports exchanges among systems implemented in the widest variety of technical environments. Its implementation should be practical in a wide variety of programming languages and operating systems. It should also support communications in a wide variety of communications environments, ranging from a full, OSI-compliant, seven level network "stack" to less complete environments, including primitive point-to-point RS 232C interconnections and transfer of data by batch media, such as floppy disk and tape.
That the standard supports immediate transfer of single transactions along with file transfers of multiple transactions.
That the standard achieves the greatest possible degree of standardization, consistent with site variations in the usage and format of certain data elements. The standard should accommodate necessary site-specific variations. This will include, at least, site-specific tables, code definitions, and possibly site-specific message segments (for example, HL7 Z segments).
That the standard must support evolutionary growth as new requirements are recognized. This includes support of the process of introducing extensions and new releases into existing operational environments.
That the HL7 organization should base the standard on experiences with existing production protocols and accepted industry-wide standard protocols. However, the standard should not favor the proprietary interests of specific companies to the detriment of other users of the standard. At the same time, HL7 seeks to preserve the unique attributes that an individual vendor can bring to the marketplace.
While it is both useful and pertinent to focus on information systems within hospitals, the long-term goal of the standard should be to define formats and protocols for computer applications in all health care environments.