The HD is designed to be a more powerful application identifier. It is also designed to be used either as a local version of a site-defined application identifier or a publicly-assigned UID. Syntactically, the HD is a group of two application identifiers: one defined by the first component, and one defined by the second and third components.
The HD allows any site to act as an assigning authority (on a local or user-defined basis), even if it technically does not have the right to issue new IDs within an identification scheme. HDs which have defined third components (defined UID types) must be unique within the series of ID's defined by that component.
3
| Comp# | Comp TBL | FHIR | ||||||
|---|---|---|---|---|---|---|---|---|
| 1 | 342 | O | - | HD.1 | namespace ID | |||
| 2 | 341 | O | - | - | HD.2 | universal ID | ||
| 3 | 343 | O | - | HD.3 | universal ID type |
5
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