What data type is used for transmitting coded values from user-defined tables?

The data type used for transmitting coded values from user-defined tables is IS, which stands for "Coded Value (External Identifier)." This data type is specifically designed to support coded values that are defined by either an organization or an outside entity. In the context of HL7, when a coded value is referenced from a user-defined set or code table, it allows for the integration of local codes that still adhere to a standardized framework.

Using the IS type ensures that the coded value is appropriately recognized and validated against the defined coding system, making it essential for consistent data exchange between systems that might use different terminologies or code sets. This is particularly important in healthcare settings where it is critical to maintain interoperability and accurate data representation across different applications and databases.

In contrast, other data types serve different purposes: CE refers to "Coded Element," which is used for coded fields but does not specifically indicate a user-defined context; HD stands for "Hierarchic Designator," often used for unique identifiers; and ID, known as "Integer Data," is simply used for Integer values, not necessarily for coded values from user-defined tables. Therefore, the IS data type is the most appropriate choice for transmitting coded values from user-defined tables.