This page is part of the FHIR Specification (v0.01: Historical Archive Draft). The current version which supercedes this version is 5.0.0. For a full list of available versions, see the Directory of published versions . Page versions: R5 R4B R4 R3 R2

Data Types

The data types include primitive types imported from XML schema, and also additional data types that capture patterns that are ubiquitious throughout the scope of the healthcare data that will be exchanged.

The data types defined on this page on this page are categorised as either "Core Types" or "Structures". "Structures" are higher level concepts that some systems internally treat differently from the "Core Types". There is no functional difference betweent the two categories, and systems are not required to treat them any differently. This table summarises the types:

  <x>1951-06-04</x>

<x xmlns="http://www.hl7.org/fhir">
  <mimeType> mand code the mime type of the content</mimeType>
  <data> opt base64Binary data inline, base64ed</data>
  <url> opt uri uri where the data can be found</url>
  <hash> opt base64Binary sha-256 hash of the data (base64 )</hash>
  <lang> opt code ISO 639-3 language code</lang>
  <title> opt string A name to display in place of the data</title>
</x>

Terminology Bindings

• Attachment.mimeType is bound to the concept domain MediaType: "The mime type of an attachment". The possible values are those specified in BCP 13 (RFCs 2045, 2046, 2047, 4288, 4289 and 2049)
• Attachment.lang is bound to the concept domain Language: "A human language". The possible values are those specified in ISO 639-3

The mimeType element must always be populated. The actual content of the Attachment can be conveyed directly using the data element, or a url reference can be provided. If both are provided, they must point to the same content. The reference can never be reused to point to different data (which means that the reference is version specific). The url reference must point to a location that resolves to actual data; some uri's such as cid: meet this requirement.

The hash is included so that applications can verify that the contents of a location have not changd, and also so that a signature of the xml content can implicitly sign the content of an image without having to include the data or reference the url in the signature. The lang element can help a consumer choose between multiple different Data elements.

In many cases where Attachment is used, the cardinality is >1; repeats are used to convey the same content in different mime types and languages, or to provide a thumbnail of a large image.

  <x>
   <mimeType>application/pdf</mimeType>
   <data>/9j/4...KAP//Z</data> <!-- covers many lines -->
   <lang type="code">en-us</lang>
   <title type="string">Definition of Procedure</title>
  </x>

  <x>
   <mimeType>application/dicom</mimeType>
   <url>http://10.1.2.3:1000/wado?requestType=WADO&wado details...</url>
   <hash>>EQH/..AgME</hash>
  </x>

<x xmlns="http://www.hl7.org/fhir">
  <system> cond uri The system that defines the id</system>
  <id> cond string the actual identifier</id>
</x>

The system may be either a specific application, or a recognised concept for which the specific application may be implicit. The system is a URI that may be an OID (oid:) or a UUID (uuid:), a sid (a specially defined URI from the named systems list), or a URL that references a definition of the identifier. OIDs and UUIDs may be registered in the HL7 OID registry, and should be if the content is shared or exchanged across institutional boundaries.

In some cases, the system may not be known - only the id is known (i.e. a simple device that scans a barcode). In this case, no useful matching may be perfomed using the id unless the system can be safely inferred by the context.

Note that the system defines the scheme that controls uniqueness of the id. The id must be unique for within the defined system. If the id itself is actually an OID, a UUID, or a URI, then the system will be either "urn:hl7-org:sid/oid", "urn:hl7-org:sid/uuid" or "urn:hl7-org:sid/uri" respectively, and the OID, UUID would be in the id element. Ids are always case sensitive. UUIDs must be represented in lower case.

  <x>
   <system>oid:2.16.840.1.113883.16.4.3.2.5</system>
   <id>123</id>
  </x>

  <x>
   <system>http://pas-server/xxx/patients</system>
   <id>443556</id>
  </x>

  <x>
   <system>urn:hl7-org:sid/uuid</system>
   <id>a76d9bbf-f293-4fb7-ad4c-2851cac77162</id>
  </x>

<x xmlns="http://www.hl7.org/fhir">
  <coding> Zero+ Coding  <!-- A reference to a code defined by a terminology system  -->
   <code> cond code Symbol in syntax defined by the system</code>
   <system> mand uri Identity of the terminology system </system>
   <display> opt string Representation defined by the system</display>
  </coding>
  <text> cond string A plain text representation of the concept</text>
  <primary> opt xml:ID Which code was chosen directly by the user</primary>
</x>

This data type has text and/or one more "codings" that all represent a single notional concept, though the multiple codings will often have slightly different granularity due to the differences in the definitions of the underlying codes. Each "coding" is a representation of the concept using a symbol from a defined "code system", which may be an enumeration, a list of codes, a full terminology such as SNOMED-CT or LOINC, or a formal ontology. The concept may be coded multiple times in different code systems (or even multiple times in the same code systems, where multiple forms are possible, such as with SNOMED-CT). Whether or not coding elements are present, the text is a human language representation of the concept as seen/selected/uttered by the user who entered the data, and/or which represents the intended meaning of the user or concept. Very often the text is the same as a display of one of the codings.

For each coding, there must be a system the identifies the terminology or ontology the code is defined by. The system is a URI that may be an OID (oid:) or a UUID (uuid:), a specially defined URI from the named systems list, or a url that references a definition of the system, or any other URI. OIDs and UUIDs may be registered in the HL7 OID registry, and should be if the content is shared or exchanged across institutional boundaries. The system reference is version independent; applications are never required to process the content of the system URI in order to determine whether two codes are the same. Note though, that merely because a code/system pair is different does not mean that concept is different - applications have to consult the ontologies or terminologies to make those kind of comparisons.

If present, the code must be a syntactically correct symbol as defined by the system. Note that codes are case sensitive unless specified otherwise by the code system. If no code is present, the coding means that the concept cannot be encoded in the identified system. The display is a text representation of the code that is defined by the system, which can be used to display the code by an application that is not aware of the system. One of the codings may be flagged as the primary - the code that the user actually chose directly. If present, the value of the primary element is an ID that must match an xml:id on one of the codings.

  <x>
    <coding>
      <code>G44.1</code>
      <system>urn:hl7-org:sid/icd-10</system>
    </coding>
    <text>general headache</text>
  </x>

  <x>
    <coding>
      <code>burn</code>
      <system>oid:2.16.840.1.113883.19.5.2</system>
    </coding>
    <coding>
      <system>http://snomed.info</system>
    </coding>
    <text>Burnt ear with iron. Burnt other ear calling for ambulance</text>
  </x>

  <x>
    <coding>
      <code>128045006:{363698007=56459004}</code>
      <system>http://snomed.info</system>
    </coding>
    <text>Cellulitis of the foot</text>
  </x>

<x xmlns="http://www.hl7.org/fhir">
  <code> cond code Selected code</code>
  <value> mand  <!-- One+ A list of possible values for the code -->
   <code> mand code Possible code</code>
   <display> opt string Display for the code</display>
  </value>
  <isOrdered> opt boolean If the order of the values has meaning</isOrdered>
</x>

The code is the selected value. A list of possible values must be provided; at least a code must be provided for each value. The selected code must be found in the list of possible codes.

If isOrdered is true, then the values have an inherent meaningful order, and the list of values must be provided in the correct order.

  <x>
    <code>+</code>
    <value>
      <code>neg</code>
    </value>
    <value>
      <code>trace</code>
    </value>
    <value>
      <code>+</code>
    </value>
    <value>
      <code>++</code>
    </value>
    <value>
      <code>+++</code>
    </value>
    <isOrdered>true</isOrdered>
  </x>

<x xmlns="http://www.hl7.org/fhir">
  <value> cond decimal Numerical value (with implicit precision)</value>
  <status> opt code how the value should be understood and represented</status>
  <units> cond string unit representation</units>
  <code> cond code A coded form of the unit</code>
  <system> cond uri The system that defines the coded form</system>
</x>

Terminology Bindings

• Quantity.status is bound to the concept domain QuantityStatus: "how the Quantity should be understood and represented". Possible values:

  <	The actual value is less than the given value
  <=	The actual value is less than or equal to the given value
  >=	The actual value is greater than or equal to the given value
  >	The actual value is greater than the given value

The value contains the numerical value of the quantity, including an implicit precision. The status indicates how the value should be understood and represented. If no status is specified, the value is a point value. The status element can never be ignored.

The units element must contain a displayable unit that defines what is measured. The units may additionally be coded in the code and the system, which is a URI, OID, or a SID that defines the code (see CodeableConcept for further information about system).

If the units are able to be coded in UCUM, and a code is provided, it SHOULD be a UCUM code. If a UCUM unit is provided in the code then a canonical value can be generated for purposes of comparison between quantities. Note that the units element will often contain text that is actually a valid UCUM unit, but it cannot be assumed that it does.

Defined Variations on Quantity

These are used as types in resource content models, but they are really just Quantity with some rules:

  <x>
    <value>25</value>
    <unit>sec</unit>
    <code>s</code>
    <system>urn:hl7-org:sid/ucum</system>
  </x>

  <x>
    <value>40000</value>
    <status>&gt;</status>
    <unit>mcg/L</unit>
    <code>ug</code>
    <system>urn:hl7-org:sid/ucum</system>
  </x>

  <x>
    <value>3</value>
    <unit>capsules</unit>
    <code>385049006</code>
    <system>http://snomed.info</system>
  </x>

  <x>
    <value>25.45</value>
    <unit>US$</unit>
    <code>USD</code>
    <system>urn:hl7-org:sid/iso-4217</system>
  </x>

An interval may be applied to Quantity, dateTime, and date. The context where the type is used must specify which of these types is used. An interval specifies a range of values; the context of use will specify whether the entire range applies (e.g. "the patient was an inpatient of the hospital for this time range") or one value from the range applies (e.g. "give the patient between 2 and 4 tablets").

<Interval xmlns="http://www.hl7.org/fhir">
  <low> cond [param] Low value (Text or elements from specified type)</low>
  <high> cond [param] High value (Text or elements from specified type)</high>
</Interval>

If the low or high elements are missing, the meaning is that the low or high boundaries are not known. A dataAbsentReason flag may be used on the low or high elements in this case. On intervals over a time period, if the high is missing, it means that the interval is current and ongoing.

If the interval applies to the Quantity type, the status flag on the quantity cannot have the values <, <=, =>, or >. Note that the Interval type should not be used to represent measurements where the status flag might be used instead.

When the interval applies to a date or dateTime, the high value includes any matching date/time. When the interval applies to the other types, the high value is assumed to have arbitrarily high precision. For example:

  <x>
   <low>
     <value>2.8</value>
     <unit>m</unit>
   </low>
   <high>
     <value>4.6</value>
     <unit>m</unit>
   </high>
  </x>

  <x>
   <low>
     <date>2011-05-23</date>
   </low>
   <high>
     <date>2011-05-27</date>
   </high>
  </x>

<x xmlns="http://www.hl7.org/fhir">
  <numerator> cond Quantity The numerator</numerator>
  <denominator> cond Quantity The denominator</denominator>
</x>

Common factors in the numerator and denominator are not automatically cancelled out. The Ratio data type is used for titers (e.g., "1:128") and other quantities produced by laboratories that truly represent ratios. Ratios are not simply "structured numerics" and blood pressure measurements (e.g. "120/60") are not ratios. In addition, ratios are used where common factors in the numerator and denominator do not cancel out. The most common example of this is where the ratio represents a unit cost, and the numerator is a currency.

  <x>
   <numerator>
     <value>1</value>
   </numerator>
   <denominator>
     <value>128</value>
   </denominator>
  </x>

  <x>
   <numerator>
     <value>103.50</value>
     <unit>US$</unit>
     <code>USD</code>
     <system>urn:hl7-org:sid/iso-4217</system>
   </numerator>
   <denominator>
     <value>128</value>
     <unit>day</unit>
     <code>day</code>
     <system>urn:hl7-org:sid/ucum</system>
   </denominator>
  </x>

Structures

<x xmlns="http://www.hl7.org/fhir">
  <type> opt Coding Code for identifier type</type>
  <identifier> cond Identifier Actual identifier</identifier>
  <period> opt Interval(dateTime) Time period when id was valid for use</period>
  <assigner> opt (Organization) Organisation that issued id</assigner>
</x>

Terminology Bindings

• HumanId.type is bound to the concept domain IdentifierType: "The type of human identifier" (sid = urn:hl7-org:sid/fhir/identifier-type). Use one of these values if possible:

  account	Account number	An identifier that is unique to an account.
  credit	Credit Card Number	A credit card number (or debit card).
  microchip	Microchip Number	implanted, for animals, or a worn RFID for humans
  registry	A Registry Number
  insurance	Insurance Scheme Member Number	Identifies the person as a member of an insurance scheme.
  national	National Healthcare Identifier	May not only be used for healthcare.
  ssn	National Social Security Number
  state	State Healthcare Identifier	May not only be used for healthcare.
  patient	Patient identifier	Frequently called MRN (medical record number) or UR (unit record number).
  facility	Facility ID
  provider	Provider number	a number allocated to a person as a provider of healthcare resources.

Note that in many cases, the assigner is used to indicate what registry/state/facility etc assigned the identifier. Another possible source for the type of an identifier is HL7 v2 table 0203.

The resource elements often use HumanId for an identifier that may be an external human mediated reference, or that may also come from a direct unambiguous reference to a resource, or may be from a seperate workflow, possibly human mediated. When the identifier is actually a direct resource reference, the type should be a resource type, the identifier.system should be the URL of the source system or, if a particular end point is not known, then "urn:hl7-org:sid/fhir/[X]" where "[X]" is the resource name , and the identifier.id should be the resource id.

  <x>
    <type>
      <code>ssn</code>
      <system>urn:hl7-org:sid/fhir/identifier-type</system>
    </type>
    <identifier>
      <system>urn:hl7-org:sid/us-ssn</system>
      <id>000111111</id>
    </identifier>
  </x>

  <x>
    <type>
      <code>patient</code>
      <system>urn:hl7-org:sid/fhir/identifier-type</system>
    </type>
    <identifier>
      <system>oid:0.1.2.3.4.5.6.7</system>
      <id>2356</id>
    </identifier>
   <period>
     <low>2009-06-05</low>
   </period>
  </x>

<x xmlns="http://www.hl7.org/fhir">
  <use> opt code The use of this name</use>
  <text> cond string Text representation of the full name</text>
  <part> cond  <!-- Zero+ A part of a name -->
   <type> opt code Type of name part (see below)</type>
   <value> mand string The content of the name part</value>
  </part>
  <period> opt Interval(dateTime) Time period when name was/is in use</period>
</x>

Terminology Bindings

• HumanName.use is bound to the concept domain NameUse: "The use of a human name". Possible values:

  usual	Known as/conventional/the one you normally use
  official	The formal name as registered in an official (government) registry, but which name might not be commonly used. May be called legal name.
  temp	A temporary name. A name valid time can provide more detailed information. This may also be used for temporary names assigned at birth or in emergency situations.
  anonymous	Anonymous assigned name, alias, or pseudonym (used to protect a person's identity for privacy reasons)
  old	This name is no longer in use (or was never correct, but retained for records)
  maiden	A name used prior to marriage. Marriage naming customs vary greatly around the world. This name use is for use by applications that collect and store maiden names. Though the concept of maiden name is often gender specific, the use of this term is not gender specific. The use of this term does not imply any particular history for a person‘s name, nor should the maiden name be determined algorithmically

• HumanName.part.type is bound to the concept domain NamePartType: "Type of a part of a human name". Possible values:

  family	Family name, this is the name that links to the genealogy. In some cultures (e.g. Eritrea) the family name of a son is the first name of his father.
  given	Given name. NOTE Not to be called first name since given names do not always come first. .
  title	Part of the name that is acquired as a title due to academic, legal, employment or nobility status etc. NOTE Title name parts include name parts that come after the name, such as qualifications.

The text element specifies the entire name as it should be represented. This may be provided instead of or as well as specific part elements. Every part must have a value.

  <x>
    <use>usual official</use>
    <part>
      <type>given</type>
      <value>Peter</value>
    </part>
    <part>
      <type>given</type>
      <value>James</value>
    </part>
    <part>
      <type>family</type>
      <value>Chalmers</value>
    </part>
  </x>

<x xmlns="http://www.hl7.org/fhir">
  <use> opt code The use of this address</use>
  <text> cond string Text representation of the address</text>
  <part> cond  <!-- Zero+ -->
   <type> opt code Type of address part (see below)</type>
   <value> mand string The content of the address part</value>
  </part>
  <period> opt Interval(dateTime) Time period when address was/is in use</period>
</x>

Terminology Bindings

• Address.use is bound to the concept domain AddressUse: "The use of an address". Possible values:

  home	A communication address at a home.
  work	An office address. First choice for business related contacts during business hours.
  temp	A temporary address. The period can provide more detailed information.
  old	This address is no longer in use (or was never correct, but retained for records)

• Address.part.type is bound to the concept domain AddressPartType: "Type of address part". Possible values:

  part	Part of an address line (typically used with an extension that further defines the meaning of the part).
  line	A line of an address (typically used for street names & numbers, unit details, delivery hints etc) .
  city	The name of the city, town, village, or other community or delivery centre.
  state	sub-unit of a country with limited sovereignty in a federally organized country. A code may be used if codes are in common use (i.e. US 2 letter state codes).
  country	Country. ISO 3166 3 letter codes can be used in place of a full country name.
  zip	A postal code designating a region defined by the postal service.
  dpid	A value that uniquely identifies the postal address. (often used in barcodes).

The text element specifies the entire address as it should be represented. This may be provided instead of or as well as specific part elements. Every part must have a value.

  <x>
   <use>work primary</use>
   <text>
       1050 W Wishard Blvd
       RG 5th floor
       Indianapolis, IN 46240
     </html>
   </text>
   <part> 
     <type>city</type>
     <value>Indianapolis</value>
   </part>
   <part> 
     <type>state</type>
     <value>IN</value>
   </part>
   <part> 
     <type>zip</type>
     <value>46240</value>
   </part>
  </x>

<x xmlns="http://www.hl7.org/fhir">
  <system> cond code What kind of contact this is</system>
  <value> cond string The actual contact details</value>
  <use> opt code How to use this address</use>
  <period> opt Interval(dateTime) Time period when the contact was/is in use</period>
</x>

Terminology Bindings

• Contact.system is bound to the concept domain ContactSystem: "What kind of contact this is". Possible values:

  phone	the value is a telephone number used for voice calls. Use of full international numbers starting with + is recommended to enable automatic dialing support but not required.
  fax	the value is a fax machine. Use of full international numbers starting with + is recommended to enable automatic dialing support but not required.
  email	the value is an email address
  url	The value is a url. This is intended for various personal contacts including blogs, twitter, facebook etc. Do not use for email addresses

• Contact.use is bound to the concept domain ContactUse: "How to use this address". Possible values:

  home	A communication contact at a home; attempted contacts for business purposes might intrude privacy and chances are one will contact family or other household members instead of the person one wishes to call. Typically used with urgent cases, or if no other contacts are available.
  work	An office contact. First choice for business related contacts during business hours.
  temp	A temporary contact. The period can provide more detailed information.
  old	This contact is no longer in use (or was never correct, but retained for records)
  mobile	A telecommunication device that moves and stays with its owner. May have characteristics of all other use codes, suitable for urgent matters, not the first choice for routine business

The value should be a properly formatted telephone number according to ITU-T E.123, but this is frequently not possible due to legacy data and/or recording methods.

  <x>
   <system>phone</system>
   <value>+15556755745</value>
   <use>home</use>
  </x>

<x xmlns="http://www.hl7.org/fhir">
  <event> mand Zero+ Interval(dateTime) When the event occurs</event>
  <repeat> opt  <!-- Only if there is none or one event -->
   <frequency> cond integer Event occurs frequency times per duration</frequency>
   <when> cond code Event occurs duration from common life event</when>
   <duration> mand Duration repeating or event-related duration</duration>
   <count> cond integer number of times to repeat</count>
   <end> cond dateTime when to stop repeats</end>
  </repeat>
</x>

Terminology Bindings

• Schedule.repeat.when is bound to the concept domain EventTiming: "A real world event that a schedule is related to". Possible values:

  HS	event occurs duration before the hour of sleep (or trying to)
  WAKE	event occurs duration after waking
  AC	event occurs duration before a meal (from the latin ante cibus)
  ACM	event occurs duration before breakfast (from the latin ante cibus matutinus)
  ACD	event occurs duration before lunch (from the latin ante cibus diurnus)
  ACV	event occurs duration before dinner (from the latin ante cibus vespertinus)
  PC	event occurs duration after a meal (from the latin post cibus)
  PCM	event occurs duration after breakfast (from the latin post cibus matutinus)
  PCD	event occurs duration after lunch (from the latin post cibus diurnus)
  PCV	event occurs duration after dinner (from the latin post cibus vespertinus)

If events are specified, at least a low must be specified for each event. If no high is specified, the event is assumed to last a limited but unknown time as clinically relevant.

If the schedule has repeating criteria, the repeat can occur a given number of times per the specified duration, or in relation to some real world event. Also, if the event repeats, a time to end the schedule can be specified, either by specifying a count number of times it can occur, or a date at which to end the schedule. If no end condition is specified, the Schedule will terminate on some criteria which is expressed elsewhere.

There are 3 rules concerning the contents of a Schedule:

1. There can only be a repeat element if there is none or one event
2. Only one of frequency and when can be present
3. Only one of count and end can be present

  <x>
    <event>
      <low>2012-01-07T09:00</low>
      <high>2012-01-07T13:00</high>
    </event>
    <event>
      <low>2012-01-14T09:00</low>
      <high>2012-01-14T13:00</high>
    </event>
    <event>
      <low>2012-01-22T11:00</low>
      <high>2012-01-22T15:00</high>
    </event>
  </x>

  <x>
   <repeat>
     <frequency>2</frequency>
     <duration>
       <value>1</value>
       <units>day</units>
       <code>d</code>
       <system>urn:hl7-org:sid/ucum</system>
     </duration>
   </repeat>
  </x>

  <x>
    <event>
      <low>2011-12-23</low>
    </event>
    <repeat>
      <when>ACM</when>
      <duration>
        <value>30</value>
        <units>min</units>
        <code>min</code>
        <system>urn:hl7-org:sid/ucum</system>
      </duration>
      <end>2012-01-02</end>
    </repeat>
  </x>

Schema & UML models

Data Types Schema.

With regard to the UML models, see notes about the UML Object models, and particularly the note regarding the UML representation of dataAbsentReason

Change History

• 20-Mar 2011: Removed version from system in Coding - version and module pushed to extensions
• 19-Mar 2011: Renamed dateTime to instant, humanDate to dateTime, and introduced date.

This is an old version of FHIR retained for archive purposes. Do not use for anything else
Implementers are welcome to experiment with the content defined here, but should note that the contents are subject to change without prior notice.
© HL7.org 2011 - 2012. FHIR v0.01 generated on Mon, May 14, 2012 09:48+1000.