Data Types


This section of the TL7 site provides additional documentation of HL7 and Canadian-customized data types.

Part of the HL7 standard is a definition of various data types used in HL7 type definitions. In many ways, HL7 data types are like standard classes in various languages such as Java, C# or XML. Types such as "Integer" (INT) and "String" (ST) are included in the HL7 definitions.

But, HL7 also includes other common data types for representing concepts that frequently arise in the health-care field, such as "Physical Quantity" (PQ) and "Ratios" (RTO).

Although the HL7 standard has defined these types, Canadian standards also play a role here. The Standards Collaborative process that establish the Canada-specific implementation of the HL7 (and other) standards have created a number of refinements to the HL7 standard datatypes. A simple example is the non-negative Integer (INT.NONNEG). These Canadian-specific data types have been documented in Data Types specification included with each Standards Collaborative release.

Data Type List

  1. Instance Identifiers (II) - including II.TOKEN, II.BUS, II.PUBLIC, etc.
  2. Codes - including CS, CV, CD and others
  3. Text - ST (String), ST.LANG, ED, ED.REF, ED.SIGNATURE, etc.
  5. Measurement - INT, INT.NONNEG, PQ (Physical Quantity)
  6. Intervals - IVL, IVL.HIGH, IVL.LOW, IVL<TS.DATE> (and other time-based intervals), IVL<PQ> (and other quantity-based interval), etc.
  7. Complex Intervals - PIVL, GTS.BOUNDEDPIVL, etc.
  8. Demographic Data - PN (Person names), TN (Trivial Names), ON (Organization names), TEL (Telecommunications Addresses), AD (Addresses)
  9. Other - BL (boolean)
Here's a summary of the data types.
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