ISO TC 215 - ISO TS 13581

ISO/TC 215 / SC WG3 NWI Proposal 679, ISO/NWIP/TS Health Informatics - Guidance for maintenance of Object Identifiers OID, 2008.

Scope

This NWIP is a proposal for a new document. It specifies principles and processes that should be exhibited by developers and data administrators of OID (Object-Identifiers)-Registries and their applicant bodies. The primary target group for this document are those establishing OID-Registries and those (Industry, government bodies) using the services maintained by such organisations. This Technical Report

• specifies procedures which are generally applicable to registration in the context of OID
• provides guidelines for the establishment and operation of Registration Authorities
• provides guidelines for additional Recommendations.

Introduction

The precise designation of objects and concepts is a prerequisite for the standardised exchange of information. Unique names, clear descriptions and responsible organisations for objects, concepts and messages are the basis for electronic data exchange. This helps to ensure international exchangeability of Objects within different applications (e.g. healthcare information systems).Versioning of OIDs and the rules of assignment are controversial issues, too. In worst case this requires re-writing of software products to reflect changes. There is a significant potential for errors to occur.

The development and maintenance of an OID Registry requires sustainable processes so that safe and consistent representation and interpretation of data and information can be supported over time. This document specifies the principles and procedures and the rules of assignment of OIDs that should be exhibited by an organization that maintain OIDs. In order to standardize these activities for at least health telematics and to ensure further interoperability it is essential to have central registers in each country and international rules for maintenance for the OID-Systems. These central registries secure the uniqueness of the OID for each concept and thereby avoid duplicates. The assignment of new OIDs is effected by following the rules of „Good practice for the assignment and usage of OIDs“ covered in this document.

OID-Registries require organisations that can accommodate the complex harmonisation of objects while maintaining longitudinal consistency and utility. Furthermore, OIDs form the foundation of many dependent systems, applications, and operations.

Terms and definitions

• object (of interest): Anything in some world, generally the world of telecommunications and information processing or some part thereof,
  • which is identifiable (can be named); and
  • which may be registered.
• object identifier tree: A specific form of tree whose root corresponds to this Technical Report and whose nodes correspond to registration authorities responsible for allocating arcs from a parent node.
• registration: The assignment of an unambiguous name and other parameters to an object in a way which makes the assignment available to interested parties.
• registration authority: An entity such as an organization, a standard or an automated facility that performs registration of one or more types of objects.

Business requirements for the maintenance of OID-Registers in health care system

Good practice for the assignment and usage of OID

The assignment of new OID is effected by following the rules of "Good practice for the assignment and usage of OID".

• The structure of the OID does not represent a hierarchy or classification. It is solely used as a reference to a description. No other relationships should be inferred from any similarities, and no internal structure of an OID should ever be relied upon within an application.
• Once an OID is assigned it will never be taken back and stays a valid identifier for this concept.
• The assigning authority, being responsible for the uniqueness of the OID, checks the content of the OID-application. (Quality check)
• If an organisation becomes registration authority within the tree of OID they can assign OID self dependently by preserving the uniqueness.
• An authority should not assign an OID for concepts or objects being used not solely within its organization. These OID should be assigned by the central registry (…for each country).
• International OID should be assigned by a central international OID-Registry.
• The description of the OID is in the English language in order to ensure interoperability with other OID registers.
• The symbolic name of an arc is required to commence with a lowercase letter, and to contain only letters, digits, and hyphens. The last character shall not be a hyphen, nor shall there be two consecutive hyphens in the name (see ITU-T Rec. X.680 | ISO/IEC 8824-1).
• The limit of the amount of characters of the OID should be 64 characters. The practical limit for an internal arc is 2^31-1.
• OID for organizations can be applied for by all organizations within the Health Care System. One organization may apply for a generally valid OID, e.g. for code systems, if it already has an organization OID registered in an OID Registry.
• Generally, the organization responsible for the OID should register the OID (e.g. WHO: ICD-10). If responsibilities are not clearly allocated, the registration centre will decide.
• Only those persons mentioned in the application may change existing OID information.
• Beneath an organization-OID the organization has the possibility of allocating new object identifiers within the scope of ISO, CEN, DIN and HL7 specifications. However, should the registered OID become generally valid, they must be reported to the national and / or International Registration Authority.
• OIDs used for code systems (CD) and Instance identifier (II) SHOULD NOT be the parent for any other OID as code systems can’t really be an assigning authority for other concepts.

Recommendations for Implementers (HL7)

There are several assumptions made in this section with regard to the way that OIDs are managed.

• The organization uses the same identifier to uniquely identify a patient across different encounters and locations. This can either be the medical record number or master patient identifier used by the organization to identify a patient.
• The organization makes use of a single electronic medical record system (EMR) across its various locations of care.
• The organization uses the same identifier to uniquely identify personnel regardless of location.
• There is a manageable number of locations, and a way to uniquely identify each of these within the scope of the organization.
• There is a manageable number of entities that the organization places orders with, and a way to uniquely identify each of these within the scope of the organization.

Content of application

The specification of the content of register entries is including at least:

1. the name assigned to the object;
2. details of the organization, applicant and contact person that proposed the entry;
3. details of the responsible organization
4. the dates of submission/registration;
5. the definition of the object in English;

Mandatory content:

1. Version
2. Desired classification (organization, code scheme, document, identification mechanism)
3. Description on the internet
4. Description by file
5. Relation to other OID
6. Comments and Questions

Recommendation for top level arcs

The recommendation is that there are six arcs specified from the node (within the healthcare system):

• 3 instance-identifier
  • 3.1 organizations
  • 3.2 persons
• 4 identification mechanism
• 5 code schemes
• 7 documents
• 99 experimental

Once an organization receives a root OID of their own, it is recommended that they create arcs below that OID using the values in the table below.

Arc	Description
.1	Documents
.2	Patients
.3	Non-licensed Personnel
.4	Locations
.5	Non-licensed Organizations
.6	Devices
.7	Encounters
.8	Orders
.9	Sections
.10	Entries
.11	Templates