For referring to data content defined in other formats.

Many models need to include data defined in other specifications that is complex and opaque to the healthcare model. This includes documents, media recordings, structured data, etc.

When providing a summary view (for example with Observation.value[x]) Attachment should be represented with a brief display text such as "Attachment".

Identifies the type of the data in the attachment and allows a method to be chosen to interpret or render the data. Includes mime type parameters such as charset where appropriate.

Processors of the data need to be able to know how to interpret the data.

The human language of the content. The value can be any valid value according to BCP 47.

Users need to be able to choose between the languages in a set of attachments.

The actual data of the attachment - a sequence of bytes. In XML, represented using base64.

The data needs to able to be transmitted inline.

The base64-encoded data SHALL be expressed in the same character set as the base resource XML or JSON.

An alternative location where the data can be accessed.

The data needs to be transmitted by reference.

If both data and url are provided, the url SHALL point to the same content as the data contains. Urls may be relative references or may reference transient locations such as a wrapping envelope using cid: though this has ramifications for using signatures. Relative URLs are interpreted relative to the service url, like a resource reference, rather than relative to the resource itself. If a URL is provided, it SHALL resolve to actual data.

The number of bytes of data that make up this attachment.

Representing the size allows applications to determine whether they should fetch the content automatically in advance, or refuse to fetch it at all.

The number of bytes is redundant if the data is provided as a base64binary, but is useful if the data is provided as a url reference.

The calculated hash of the data using SHA-1. Represented using base64.

Included so that applications can verify that the contents of a location have not changed and so that a signature of the content can implicitly sign the content of an image without having to include the data in the instance or reference the url in the signature.

A label or set of text to display in place of the data.

Applications need a label to display to a human user in place of the actual data if the data cannot be rendered or perceived by the viewer.

The date that the attachment was first created.

This is often tracked as an integrity issue for use of the attachment.

A technical identifier - identifies some entity uniquely and unambiguously.

Need to be able to identify things with confidence and be sure that the identification is not subject to misinterpretation.

The purpose of this identifier.

Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

This is labeled as "Is Modifier" because applications should not mistake a temporary id for a permanent one. Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

Allows users to make use of identifiers when the identifier system is not known.

Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

Establishes the namespace in which set of possible id values is unique.

There are many sequences of identifiers. To perform matching, we need to know what sequence we're dealing with. The system identifies a particular sequence or set of unique identifiers.

The portion of the identifier typically displayed to the user and which is unique within the context of the system.

If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986.

Time period during which identifier is/was valid for use.

Organization that issued/manages the identifier.

The reference may be just a text description of the assigner.

A reference to a code defined by a terminology system.

References to codes are very common in healthcare models.

Codes may be defined very casually in enumerations or code lists, up to very formal definitions such as SNOMED CT - see the V3 Core Principles for more information.

The identification of the code system that defines the meaning of the symbol in the code.

Need to be unambiguous about the source of the definition of the symbol.

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Need to refer to a particular code in the system.

A representation of the meaning of the code in the system, following the rules of the system.

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Indicates that this code was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

This has been identified as a clinical safety criterium - that this exact code was chosen explicitly, rather than inferred by the system based on some rules or language processing.

Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations.

A concept that may be defined by a formal reference to a terminology or ontology or may be provided by text.

This is a common pattern in healthcare - a concept that may be defined by one or more codes from formal definitions including LOINC and SNOMED CT, and/or defined by the provision of text that captures a human sense of the concept.

Not all terminology uses fit this general pattern. In some cases, models should not use CodeableConcept and use Coding directly and provide their own structure for managing text, codings, translations and the relationship between elements and pre- and post-coordination.

A reference to a code defined by a terminology system.

Allows for translations and alternate encodings within a code system. Also supports communication of the same instance to systems requiring different encodings.

Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the V3 Core Principles for more information. Ordering of codings is undefined and SHALL not be used to infer meaning.

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.

The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

Very often the text is the same as a displayName of one of the codings.

A measured amount (or an amount that can potentially be measured). Note that measured amounts include amounts that are not precisely quantified, including amounts involving arbitrary units and floating currencies.

Need to able to capture all sorts of measured values, even if the measured value are not precisely quantified. Values include exact measures such as 3.51g, customary units such as 3 tablets, and currencies such as $100.32USD.

The context of use may frequently define what kind of quantity this is and therefore what kind of units can be used. The context of use may also restrict the values for the comparator.

The value of the measured amount. The value includes an implicit precision in the presentation of the value.

Precision is handled implicitly in almost all cases of measurement.

The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues. E.g. if the comparator is "<" , then the real value is < stated value.

Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value.

A human-readable form of the units.

There are many representations for units and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

The identification of the system that provides the coded form of the unit.

Need to know the system that defines the coded form of the unit.

A computer processable form of the units in some unit representation system.

Need a computable form of the units that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency.

The context of use may additionally require a code from a particular system.

A set of ordered Quantities defined by a low and high limit.

Need to be able to specify ranges of values.

The stated low and high value are assumed to have arbitrarily high precision when it comes to determining which values are in the range. I.e. 1.99 is not in the range 2 -> 3.

The low limit. The boundary is inclusive.

If the low element is missing, the low boundary is not known.

The high limit. The boundary is inclusive.

If the high element is missing, the high boundary is not known.

A relationship of two Quantity values - expressed as a numerator and a denominator.

Need to able to capture ratios for some measurements (titers) and some rates (costs).

The value of the numerator.

The value of the denominator.

A time period defined by a start and end date and optionally time.

This is not a duration - that's a measure of time (a separate type), but a duration that occurs at a fixed value of time. A Period specifies a range of time; 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 to the patient between these two times"). If a duration might be required, specify the type as Interval|Duration.

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means that the period is ongoing.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has a end value of 2012-02-03.

A series of measurements taken by a device, with upper and lower limits. There may be more than one dimension in the data.

There is a need for a concise way to handle the data produced by devices that sample a physical state at a high frequency.

The data is not interpretable without at least origin, period, and dimensions, but these are optional to allow a separation between the template of measurement and the actual measurement, such as between DeviceCapabilities and DeviceLog. When providing a summary view (for example with Observation.value[x]) SampledData should be represented with a brief display text such as "Sampled Data".

The base quantity that a measured value of zero represents. In addition, this provides the units of the entire measurement series.

The length of time between sampling times, measured in milliseconds.

This is usually a whole number.

A correction factor that is applied to the sampled data points before they are added to the origin.

The lower limit of detection of the measured points. This is needed if any of the data points have the value "L" (lower than detection limit).

The upper limit of detection of the measured points. This is needed if any of the data points have the value "U" (higher than detection limit).

The number of sample points at each time point. If this value is greater than one, then the dimensions will be interlaced - all the sample points for a point in time will be recorded at once.

If there is more than one dimension, the code for the type of data will define the meaning of the dimensions (typically ECG data).

A series of data points which are decimal values separated by a single space (character u20). The special values "E" (error), "L" (below detection limit) and "U" (above detection limit) can also be used in place of a decimal value.

A human's name with the ability to identify parts and usage.

Need to be able to record names, along with notes about their use.

Names may be changed, or repudiated, or people may have different names in different contexts. Names may be divided into parts of different type that have variable significance depending on context, though the division into parts does not always matter. With personal names, the different parts may or may not be imbued with some implicit meaning; various cultures associate different importance with the name parts and the degree to which systems must care about name parts around the world varies widely.

Identifies the purpose for this name.

Allows the appropriate name for a particular context of use to be selected from among a set of names.

This is labeled as "Is Modifier" because applications should not mistake a temporary or old name etc for a current/permanent one. Applications can assume that a name is current unless it explicitly says that it is temporary or old.

A full text representation of the name.

A renderable, unencoded form.

Can provide both a text representation and structured parts.

The part of a 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.

For family name, hyphenated names such as "Smith-Jones" are a single name, but names with spaces such as "Smith Jones" are broken into multiple parts.

Given name.

If only initials are recorded, they may be used in place of the full name. Not called "first name" since given names do not always come first.

Part of the name that is acquired as a title due to academic, legal, employment or nobility status, etc. and that appears at the start of the name.

Part of the name that is acquired as a title due to academic, legal, employment or nobility status, etc. and that appears at the end of the name.

Indicates the period of time when this name was valid for the named person.

Allows names to be placed in historical context.

There is a variety of postal address formats defined around the world. This format defines a superset that is the basis for all addresses around the world.

Need to be able to record postal addresses, along with notes about their use.

Note: address is for postal addresses, not physical locations.

The purpose of this address.

Allows an appropriate address to be chosen from a list of many.

This is labeled as "Is Modifier" because applications should not mistake a temporary or old address etc for a current/permanent one. Applications can assume that an address is current unless it explicitly says that it is temporary or old.

A full text representation of the address.

A renderable, unencoded form.

Can provide both a text representation and parts.

This component contains the house number, apartment number, street name, street direction, P.O. Box number, delivery hints, and similar address information.

home | work | temp | old - purpose of this address.

The name of the city, town, village or other community or delivery center.

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).

A postal code designating a region defined by the postal service.

Country - a nation as commonly understood or generally accepted.

ISO 3166 3 letter codes can be used in place of a full country name.

Time period when address was/is in use.

Allows addresses to be placed in historical context.

Details for All kinds of technology mediated contact points for a person or organization, including telephone, email, etc.

Need to track phone, fax, mobile, sms numbers, email addresses, twitter tags, etc.

Telecommunications form for contact point - what communications system is required to make use of the contact.

The actual contact point details, in a form that is meaningful to the designated communication system (i.e. phone number or email address).

Need to support legacy numbers that are not in a tightly controlled format.

Additional out of band data such as extensions, or notes about use of the contact are sometimes included in the value.

Identifies the purpose for the contact point.

Need to track the way a person uses this contact, so a user can choose which is appropriate for their purpose.

This is labeled as "Is Modifier" because applications should not mistake a temporary or old contact etc for a current/permanent one. Applications can assume that a contact is current unless it explicitly says that it is temporary or old.

Time period when the contact point was/is in use.

Specifies an event that may occur multiple times. Timing schedules are used to record when things are expected or requested to occur. The most common usage is in dosage instructions for medications. They are also used when planning care of various kinds.

Need to able to track proposed timing schedules. There are several different ways to do this: one or more specified times, a simple rules like three times a day, or before/after meals.

A timing schedule can be either a list of events - intervals on which the event occurs, or a single event with repeating criteria or just repeating criteria with no actual event. When both event and a repeating specification are provided, the list of events should be understood as an interpretation of the information in the repeat structure.

Identifies specific times when the event occurs.

In an MAR, for instance, you need to take a general specification, and turn it into a precise specification.

A set of rules that describe when the event should occur.

Many timing schedules are determined by regular repetitions.

Outer bounds for start and/or end limits of the timing schedule.

A total count of the desired number of repetitions.

Repetitions may be limited by end time or total occurrences.

If you have both bounds and count, then this should be understand as within the bounds period, until count times happens.

How long this thing happens for when it happens.

Some activities are not instantaneous and need to be maintained for a period of time.

For some events the duration is part of the definition of the event (e.g. IV infusions). For others, it's part of the timing specification (e.g. exercise).

The units of time for the duration, in UCUM units.

The number of times to repeat the action within the specified period / period range (i.e. both period and periodMax provided).

If present, indicates that the frequency is a range - so repeat between [frequency] and [frequencyMax] times within the period or period range.

Indicates the duration of time over which repetitions are to occur. E.g. to express "3 times per day", 3 would be the frequency and "1 day" would be the period.

If present, indicates that the period is a range from [period] to [periodMax], allowing expressing concepts such as "do this once every 3-5 days.

The units of time for the period in UCUM units.

A real world event that the occurrence of the event should be tied to.

Timings are frequently determined by occurrences such as waking, eating and sleep.

A code for the timing pattern. Some codes such as BID are uniquitious, but many instutions define their own additional codes.

A repeat should always be defined except for the common codes BID, TID, QID, AM and PM, which all systems are required to understand.

An XML digital signature along with supporting context.

There are a number of places where content must be signed in healthcare.

The elements of the Signature Resource are for ease of access of these elements. The non-repudiation proof comes from the XML-Signature validation, which includes validation of the referenced objects (e.g., Resources) (a.k.a., Content) in the XML-Signature Detached form.

An indication of the reason that the entity signed this document. This may be explicitly included as part of the signature information and can be used when determining accountability for various actions concerning the document.

Examples include attesting to: authorship, correct transcription, and witness of specific event. Also known as a “Commitment Type Indication”.

When the digital signature was signed.

This should agree with the information in the signature.

A reference to an application-usable description of the person that signed the certificate (e.g. the signature used their private key).

This should agree with the information in the signature.

The base64 encoding of the XML-Signature.

Where the signed content is a FHIR Resource(s), the signature is of the XML form of the Resource(s) using XML-Signature (XMLDIG) "Detached Signature" form.