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ISO 21090 Data Type Extensions

FHIR Infrastructure Work GroupMaturity Level: N/AStandards Status: Informative

Scope and Usage

This profile defines a large number of extensions that reflect capabilities of the ISO 21090 data types specification that were not included as part of the FHIR core data types specification. (These capabilities were excluded because it was determined that they represented "edge case" capabilities that the majority of existing implementations did not support.

At the present time, this profile is incomplete. It only contains extensions reflecting capabilities that have been explicitly identified as "useful" in the context of FHIR. The set of extensions in this profile will continue to grow over time until eventually all capabilities of the ISO 21090 specification are reflected.

For ease of reading, the extensions have been organized based on the underlying data type in the ISO specification. The applicable FHIR data type(s) are also identified.

NOTE: FHIR uses a different architecture than HL7 v3, so some capabilities might not make sense in the FHIR context or may need to be used in a different manner. Where necessary, guidance is included in this profile on any differences in usage.

Any (ANY)

These extensions may apply to any of the FHIR data types (complex or primitive). It can also appear on any resource element.


This extension allows exceptional values to be conveyed, as well as for data to be flagged as "missing" for some reason.

In v3, null flavors were often required for data types when particular components were missing. In the FHIR core specification, there is never an automatic requirement to send a null flavor, though profiles may introduce such a requirement. As well, the need for null flavors is often made explicit in the specification by adding relevant null flavors to the value set for coded elements or by introducing a "choice" of data type such that either a normal value or a coded special value can be specified. For example, a resouce might have a quantity[x] element with a type of Quantity | code where the value set is limited to TRC, QS or UNK. In this way, only those null flavors that are relevant to the context are included.

Where null flavors are not supported as part of the core specification, extensions can be defined that expose only those null flavors that are relevant. This approach is preferred over referencing the full null flavor specification. (Note that the null flavor code system can be referenced in any value sets.)

Entity Name (EN)

These extensions apply to the HumanName data type.

  • EN-use - allows a more refined statement of the intended use of a particular name
  • EN-representation - is for a subset of EN-use and indicates the representation form of the name (this has specific use in east Asian countries)

This extension applies to HumanName parts - e.g. family and given:

  • EN-qualifier - allows distinguishing initials, middle names, call-me names and other types of names

Note, however, that subsequent implementer experience has led to a new set of extensions being defined for most of the human name issues (see own-name, own-prefix, partner-name, partner-prefix, fathers-family and mothers-family), and these should be used in preference to the ISO 21090 extensions, which are defined only for backwards compatibility.

Parametric Probability Distribution of a Physical Quantity (PPD<PQ>)

These extensions provide support for the probability distributions for the Quantity data type. There are two properties:

  • uncertainty - Indicates the standard deviation associated with the extended quantity.
  • uncertaintyType - Identifies the probability distribution associated with the uncertainty of the extended quantity.

Address (AD)

These extensions provide support for various additional properties of the Address data type. There are kinds of properties:

These additional elements of Address will be ignored by applications that do not support them, so any information in them should also be duplicated in the Address.line to which they are attached.


iso21090-nullFlavornullFlavor :

If the value is not a proper value, indicates the reason.

iso21090-EN-qualifierEN-qualifier :

A set of codes each of which specifies a certain subcategory of the name part in addition to the main name part type.

iso21090-EN-useEN-use :

A set of codes advising a system or user which name in a set of names to select for a given purpose.

iso21090-EN-representationEN-representation :

Name Representation.

iso21090-uncertaintyuncertainty :

The primary measure of variance/uncertainty of the value (the square root of the sum of the squares of the differences between all data points and the mean).

iso21090-uncertaintyTypeuncertaintyType :

A code specifying the type of probability distribution for the uncertainty.

iso21090-AD-useAD-use :

Uses of Addresses - codes not defined as part of Address.use.

iso21090-ADXP-additionalLocatorADXP-additionalLocator :

This can be a unit designator, such as apartment number, suite number, or floor. There may be several unit designators in an address (e.g., "3rd floor, Appt. 342"). This can also be a designator pointing away from the location, rather than specifying a smaller location within some larger one (e.g., Dutch "t.o." means "opposite to" for house boats located across the street facing houses).

iso21090-ADXP-unitIDADXP-unitID :

The number or name of a specific unit contained within a building or complex, as assigned by that building or complex.

iso21090-ADXP-unitTypeADXP-unitType :

Indicates the type of specific unit contained within a building or complex. E.g. Appartment, Floor.

iso21090-ADXP-deliveryAddressLineADXP-deliveryAddressLine :

A delivery address line is frequently used instead of breaking out delivery mode, delivery installation, etc. An address generally has only a delivery address line or a street address line, but not both.

iso21090-ADXP-deliveryInstallationTypeADXP-deliveryInstallationType :

Indicates the type of delivery installation (the facility to which the mail will be delivered prior to final shipping via the delivery mode.) Example: post office, letter carrier depot, community mail center, station, etc.

iso21090-ADXP-deliveryInstallationAreaADXP-deliveryInstallationArea :

The location of the delivery installation, usually a town or city, and is only required if the area is different from the municipality. Area to which mail delivery service is provided from any postal facility or service such as an individual letter carrier, rural route, or postal route.

iso21090-ADXP-deliveryInstallationQualifierADXP-deliveryInstallationQualifier :

A number, letter or name identifying a delivery installation. For example, for Station A, the delivery installation qualifier would be 'A'.

iso21090-ADXP-deliveryModeADXP-deliveryMode :

Indicates the type of service offered, method of delivery. For example: post office box, rural route, general delivery, etc.

iso21090-ADXP-deliveryModeIdentifierADXP-deliveryModeIdentifier :

Represents the routing information such as a letter carrier route number. It is the identifying number of the designator (the box number or rural route number).

iso21090-ADXP-streetAddressLineADXP-streetAddressLine :

A street address line is frequently used instead of breaking out building number, street name, street type, etc. An address generally has only a delivery address line or a street address line, but not both.

iso21090-ADXP-houseNumberADXP-houseNumber :

The number of a building, house or lot alongside the street. Also known as "primary street number". This does not number the street but rather the building.

iso21090-ADXP-buildingNumberSuffixADXP-buildingNumberSuffix :

Any alphabetic character, fraction or other text that may appear after the numeric portion of a building number.

iso21090-ADXP-postBoxADXP-postBox :

A numbered box located in a post station.

iso21090-ADXP-houseNumberNumericADXP-houseNumberNumeric :

The numeric portion of a building number.

iso21090-ADXP-streetNameADXP-streetName :


iso21090-ADXP-streetNameBaseADXP-streetNameBase :

The base name of a roadway or artery recognized by a municipality (excluding street type and direction).

iso21090-ADXP-streetNameTypeADXP-streetNameType :

The designation given to the street. (e.g. Street, Avenue, Crescent, etc.).

iso21090-ADXP-directionADXP-direction :

Direction (e.g., N, S, W, E).

iso21090-ADXP-careOfADXP-careOf :

The name of the party who will take receipt at the specified address, and will take on responsibility for ensuring delivery to the target recipient.

iso21090-ADXP-censusTractADXP-censusTract :

A geographic sub-unit delineated for demographic purposes.

iso21090-ADXP-delimiterADXP-delimiter :

Delimiters are printed without framing white space. If no value component is provided, the delimiter appears as a line break.

iso21090-ADXP-precinctADXP-precinct :

A subsection of a municipality.

iso21090-codedStringcodedString :

Provides a coded expression for the content represented in a string.

iso21090-preferredpreferred :

Flag denoting whether parent item is preferred - e.g., a preferred address or telephone number.

iso21090-TEL-addressTEL-address :

A V3 compliant, RFC 3966 conformant URI version of the telephone or fax number.