HL7 OID Registry Frequently Asked Questions

I already have an OID, does HL7 have to assign a new one?

No. There are two separate operations, the creation of an OID under the HL7 root, and the registration of an OID. When you select “Internal” on the form data entry page, HL7 will create an OID under the HL7 root and register it. If you select “External” on that page, you must enter the literal numeric form (dots and numbers) of the OID you already have, which will then be registered.

I have no idea what Type I should select for my OID

HL7 has created a Type ontology for the OIDs in the HL7 registry to make it easier for the user community to search for OIDs they may be looking for; this type has nothing to do with ISO standards, or any intrinsic meaning or form of the OID itself. It is only a convenience for the users of this Registry.

The following Types have been defined for use in the HL7 OID Registry:

• Type 1

HL7 registered internal objects (other than published documents and organizational bodies)

Type 1 OIDs are only used for certain internal administrative functions at this time.

• Type 2

HL7 organizational bodies and groups

Type 2 OIDs are only used to identify an HL7 Group, such as a Working Group, or an International Council Member of HL7, such as HL7 Australia.

• Type 3

External group functioning as a Registration Authority

Type 3 OIDs are used for organizations that wish to create their own trees of OIDs for their use. If you will be assigning OIDs yourself under the OID that you are applying for, then you should select Type 3. This effectively delegates Registration Authority to your organization for all OIDs under this new Type 3 OID. No one else anywhere will create OIDs under your new root. Every OID created ‘under’ this new root will be considered by HL7 to be an ‘external’ OID, since you will have created it external to the HL7 OID Registry OID assignment software. These may be requested or registered by anyone.

• Type 4

Registered externally maintained identifier systems and namespaces

Type 4 OIDs are used for namespaces for identifiers that are public, and used widely, such as health card numbers, ID numbers assigned by jurisdictional authorities, etc. This is also used for any namespaces you may manage with your own defined OIDs under your own root, such as Medical Record Numbers or Accession Numbers, for example. This type of OID is typically used in the root of the version 3 datatype Instance Identifier.

• Type 5

HL7 Internal Code Systems

Type 5 OIDs are used only for HL7 created and maintained Coding Systems, that have been approved through the HL7 V3 Harmonization process. This type is assigned only by the group that applies decisions from the harmonization processes to the HL7 databases. These OIDs are typically used in the codSystem property of an HL7 Version 3 coded datatype.

• Type 6

Registered external coding systems

Type 6 is assigned to those OIDs that identify a Coding System or terminology that is created, published, and maintained by any organization outside of HL7. At this time, only an HL7 cochair or OID administrator can assign Type 6 to any OID. This type of OID is typically used in the codeSystem property of an HL7 Version 3 coded datatype.

• Type 7

HL7 published documents

Type 7 OIDs are used solely for HL7 published artifacts, and are assigned only by members of the HL7 publishing group. This includes standards, tutorial slides, implementation guides, databases, published RIM graphic billboards, etc.

• Type 8

HL7 OID registered documentation products and artifacts

Type 8 is currently not used.

• Type 9

HL7 Registered conformance profiles

Type 9 is used to indicate HL7 Conformance Profiles, published in the HL7 Profile Registry.

• Type 10

HL7 Registered Templates

Type 10 OIDs identify published Templates. These are created and registered by the Templates Workgroup, or by HL7 Workgroups that define and publish templates as part of their balloted standards.