Release 4 4B

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Element-definition Extensions for use by FHIR Implementers

FHIR Infrastructure Work Group Maturity Level : N/A Standards Status : Informative

Scope and Usage

This profile defines extensions that can be used to describe the additional characteristics that must be held by a data element.

Data elements can be defined in several places. The extensions defined within this profile may apply to most or all of these:

  • StructureDefinition .*.element - defining the characteristics of the data elements and extensions when used according to the profile
  • Questionnaire .group.question - defining the characteristics of permitted answers

Note: Implementations are not required to reject invalid data. However, transmitting data that violates one of these extensions would be considered invalid against the resource that declared the extension.

The extensions provided here fall into several categories:

Content

Extensions :
minLength minLength :

The minimum number of characters that must be present in the simple data type to be considered a "valid" instance.

regex regex :

A regular expression that defines the syntax for the data element to be considered valid.

entryFormat entryFormat :

Additional instructions for the user to guide their input (i.e. a human readable version of a regular expression like "nnn-nnn-nnn"). In most UIs this is the placeholder (or 'ghost') text placed directly inside the edit controls and that disappear when the control gets the focus.

minValue minValue :

The inclusive lower bound on the range of allowed values for the data element.

maxValue maxValue :

The inclusive upper bound on the range of allowed values for the data element.

maxDecimalPlaces maxDecimalPlaces :

Identifies the maximum number of decimal places that may be specified for the data element.

mimeType mimeType :

Identifies the kind(s) of attachment allowed to be sent for an element.

maxSize maxSize :

For attachment answers, indicates the maximum size an attachment can be.