Use of HL7 templates in CP
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Use of Templates in Care Provision
HL7 Templates
An HL7 template is a constraint on models based on the HL7 Reference Information Model (RIM). It expresses the data content needed in a specific clinical or administrative context. In healthcare there are prescribed patterns by which, for example, multiple observations may be combined to describe selected, gross observations. Some observations may be simple, such as the single lab result (e.g. potassium in blood is 4.4 mEq/L) or the blood pressure concept, which involves a set of expected observations (i.e., systolic, diastolic, patient position, method, etc.). Other more elaborate diagnostic procedures may involve hundreds of related pieces of information, including anatomy, orientation, sequences of measurements, etc. In HL7, more or less generic models exist; the Patient Care model, especially the Care Statements = Clinical Statement Pattern (CSP) is one of it. Templates provide a method of describing rules for combining and constraining HL7 v3 XML instances like a Patient Care message. Templates can be used for three purposes:
- To have a guideline to create (a fragment of) a Patient Care message instance
- To validate an instance whether it conforms to the specified template rules
- To have a guidance while processing a Patient Care message instance.
Based on user need and preference, the template ideally is a structure that can be used as a building block and, once defined, can be re-used whenever appropriate.
Kinds of Patient Care templates
The Patient Care standard describes conformance requirements in terms of two general levels:
- Message root level templates: they define / refine the overall structure of a message starting from the Care Provision class, which templates are contained in the message and whether they are optional or required.
- Substructure level templates (patient, provider etc.)
- Clinical Statement level templates: impose the Clinical Statement Pattern of a Patient Care message; they define the constraints on the classes, class attributes, data types and class relationships.