The HL7 message position refers to a syntax used to describe a specific piece of data in an HL7 message. An HL7 message is a hierarchy of data elements called segments, fields, components, and subcomponents.
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A message includes multiple segments.
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A segment includes multiple fields.
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A field may include multiple components.
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A component may include multiple subcomponents.
To describe the position of data within the HL7 message, use the following syntax:
Segment ID.Field#[.Component#[.Subcomponent#]]
Note:
Component# and SubComponent# are optional. Not every field has multiple components or subcomponents.
For example:
PID.3.1
This position refers to the first component of the third field of the PID segment.