Path | Short | Definition | Comments |
---|---|---|---|
A list is a curated collection of resources | A list is a curated collection of resources. | ||
identifier | Business identifier | Identifier for the List assigned for business purposes outside the context of FHIR. | |
status | current | retired | entered-in-error | Indicates the current state of this list. | This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid. |
mode | working | snapshot | changes | How this list was prepared - whether it is a working list that is suitable for being maintained on an ongoing basis, or if it represents a snapshot of a list of items from another source, or whether it is a prepared list where items may be marked as added, modified or deleted. | This element is labeled as a modifier because a change list must not be misunderstood as a complete list. |
title | Descriptive name for the list | A label for the list assigned by the author. | |
code | What the purpose of this list is | This code defines the purpose of the list - why it was created. | If there is no code, the purpose of the list is implied where it is used, such as in a document section using Document.section.code. |
subject | If all resources have the same subject | The common subject (or patient) of the resources that are in the list if there is one. | Some purely arbitrary lists do not have a common subject, so this is optional. |
encounter | Context in which list created | The encounter that is the context in which this list was created. | |
date | When the list was prepared | The date that the list was prepared. | The actual important date is the date of currency of the resources that were summarized, but it is usually assumed that these are current when the preparation occurs. |
source | Who and/or what defined the list contents (aka Author) | The entity responsible for deciding what the contents of the list were. Where the list was created by a human, this is the same as the author of the list. | The primary source is the entity that made the decisions what items are in the list. This may be software or user. |
orderedBy | What order the list has | What order applies to the items in the list. | Applications SHOULD render ordered lists in the order provided, but MAY allow users to re-order based on their own preferences as well. If there is no order specified, the order is unknown, though there may still be some order. |
note | Comments about the list | Comments that apply to the overall list. | |
entry | Entries in the list | Entries in this list. | If there are no entries in the list, an emptyReason SHOULD be provided. |
entry.id | Unique id for inter-element referencing | Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces. | |
entry.extension | Additional content defined by implementations | May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone. |
entry.modifierExtension | Extensions that cannot be ignored even if unrecognized | May be used to represent additional information that is not part of the basic definition of the element and that modifies the understanding of the element in which it is contained and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions. Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself). | There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone. |
entry.flag | Status/Workflow information about this item | The flag allows the system constructing the list to indicate the role and significance of the item in the list. | The flag can only be understood in the context of the List.code. If the flag means that the entry has actually been deleted from the list, the deleted element SHALL be true. Deleted can only be used if the List.mode is "changes". |
entry.deleted | If this item is actually marked as deleted | True if this item is marked as deleted in the list. | If the flag means that the entry has actually been deleted from the list, the deleted element SHALL be true. Both flag and deleted can only be used if the List.mode is "changes". A deleted entry should be displayed in narrative as deleted. This element is labeled as a modifier because it indicates that an item is (to be) no longer in the list. |
entry.date | When item added to list | When this item was added to the list. | |
entry.item | Actual entry | A reference to the actual resource from which data was derived. | |
emptyReason | Why list is empty | If the list is empty, why the list is empty. | The various reasons for an empty list make a significant interpretation to its interpretation. Note that this code is for use when the entire list has been suppressed, and not for when individual items are omitted - implementers may consider using a text note or a flag on an entry in these cases. |
The List resource is a flat, possibly ordered collection of records. List resources are used in many places, including allergies, medications, alerts, family history, medical history, etc. List resources can be used to support patient-specific clinical lists as well as lists that manage workflows such as tracking patients, managing teaching cases, etc. Resources supported by the List resource can be homogeneous – consisting of only one type of resource (e.g. allergy lists) as well as heterogeneous – containing a variety of resources (e.g. a problem list including Conditions, AllergyIntolerances, recent Procedures, etc.).
Lists will typically include references to the resources that make up the list, however in some cases the details of the content of the list might be expressed in narrative only; e.g. a text record of a family history. The List resource is only needed if there is a need to filter the set of resources by a mechanism that cannot be accomplished via a simple query; e.g. there is no need to have a list for all AllergyIntolerances that exist on a server for a given patient. However, List is an appropriate mechanism to provide a filtered list of the subset of AllergyIntolerances that are deemed to be "current". Lists are allowed to contain other Lists, to create a nested collection of Lists.
Querying a List of resources such as AllergyIntolerance, Condition or Medication-related resources is different than querying the resource-specific endpoint. For example, a List of AllergyIntolerance resources would represent a curated point-in-time snapshot of the patient's allergies and intolerances. On the other hand, querying the AllergyIntolerance endpoint would typically produce a larger set of records as it would both be non-curated (potentially containing duplicate or out-of-date records) and current - generated based on information as of "now" rather than the last time a human manually revised the List resource instance. Which mechanism is most appropriate for data retrieval will vary by use-case. In some cases, systems might not have an appropriate curated List to query.
Note that the presence of an item in a List resource SHALL NOT change the meaning of any information that would be
understood by looking at the item outside the context of the List, because items may be accessed directly outside
the List by RESTful means or after a document is processed. For example, a List with a code that means
"refuted conditions" cannot have items that are Condition resources that do not have a
Condition.clinicalStatus
of refuted.
There are five mechanisms in FHIR for communicating collections of resources:
contained
element - allows multiple resources to be nested
inside any DomainResource. This is a special type of grouping where the grouped resources lose independent existence - they
no longer have their own identifiers, can't easily be queried independently, etc. Use of this grouping is a technical
mechanism for managing the independence of resources and has no impact on meaning. Contained, bundled, and remotely referenced
resources convey the same meaning.
When a client system is interested in a patient's medications, allergies, problems, family history or other information typically handled via List, they have three options:
Querying directly against the clinical resource endpoints will provide an un-curated view of information. A server may contain records that were part of various clinical documents, referrals and other submission sources that might not necessarily be considered wholly accurate or current, but which must be retained "as is" to provide a record of what data was received or seen by a clinician at a particular point in time.
On the other hand, lists are almost always curated. They will include only those records deemed by the author of the list to be both current and accurate. This can be both an advantage and a disadvantage. Lists are less likely to include irrelevant content, but there's a risk that they won't be completely up-to-date (new content may have been added that's more recent than when a given list was last updated). It's also possible that the list author's notion of "current" or "relevant" may differ from the perspective of the user performing the query. Also, there's the challenge that multiple lists may exist, with different author and different perspectives
The Current resource lists get around the problem of multiple lists and make it clear which list is considered authoritative, but not all systems will necessarily support this capability, and there's still the possibility that the list won't be completely up-to-date or will exclude information that is of interest to the querying system.
There's no right and wrong way to retrieve allergy, medication and other such information. Sometimes retrieving the "current" medication list will provide the best results, sometimes querying the raw records will provide better results. Sometimes providing the contents of the list plus a filtered view of the raw records may give the most useful information. Determining the most appropriate approach will depend on the needs of the user as well as the types of data sources for information held on the server and patterns of list maintenance. Client systems may well need to adapt their behavior in different environments if they can't count on consistent server behavior.
All lists are considered ordered - the order in which items literally appear in the list may be an important part of the meaning of the list. Reordering the items in a list may change the meaning of the list.
While a list always contains an ordered set of items, the significance of the order may be unknown, or it may be insignificant. As an example, consider a list of patients for a practitioner to visit. The list may be in the order in which the patients are to be visited, or it may be an unsorted list of patients to be visited in any order.
The List resource has an orderedBy
element that, if
present, specifies the meaning of the item order. Note, however,
that the meaning of the order may be known implicitly rather
than specified in the orderedBy
element.
Applications SHOULD NOT reorder the elements in a list unless they understand the impact of this on the meaning of the list.
There are several different kinds of uses for a List resource:
[%codelist http://hl7.org/fhir/list-mode%]The most common mode is "snapshot" - a list that is accurate within the context it is used in but not current or maintained after that; e.g., medications on discharge in a discharge summary. Note that these lists usually have a status of 'current' - they were current when they were prepared. Some kinds of lists may be explicitly retired (particularly if mode = working), but most will not be maintained after creation.
A change list may include deleted items. Some examples of change lists are a reconciled list of allergies, a discharge medication list and a list with new, updated and deleted items in it - though these might not be lists that include changes (this is an implementation decision). In order to ensure that the list is safe to process, any item where the flag implies that the item has actually been deleted SHALL have the deleted element set to true.
Note that there is no implication about the status of a resource that has been deleted. The only statement that is made is that the resource has been dropped from the list. However, applications should ensure that the implication of adding or deleting items from the list is consistent with the logical status of the resource and its contents.
A proper use of List.mode = "changes" with a deleted resource is in a medications list section of a discharge summary. See Example "med-list". An improper use would be if the list was a working list of patient medications in a clinical tracking system, and list item flags were used to implement version tracking history within the resource.
Some kinds of List
resources may grow to a considerable size, and
handling them may require more care than typical resources. Some approaches
to consider include:
The narrative portion of the List resource should contain a summary of the items in the list, their key information, along with a human-readable summary of their flags (if present). The narrative may be generated from the data content and/or narrative of the resources referred to in the list, or it may be a narrative written by a human, which is partially or completely matched by structured data in the linked resources. The human written narrative may be the only content if the list has no entries (which would equate to a narrative only section in a document).
An HTML table is the recommended approach, though this is not required. Each List.item should appear in the narrative for the resource; i.e. it SHALL NOT be necessary to retrieve the list items in order to have a human-readable rendering of the content. In addition, if the List.text.status is "generated", then the narrative should not suggest the list contains items for which there are no corresponding List.item elements. If the list has flags, the representation should make clear use of visual hints (borders, lines, bullet marks, etc.) to ensure that human readers do not get confused about which flags belong with which item on space-poor displays (e.g. to prevent wrapping from separating the flags from the items).
Note that when a List resource is used in a Document, the narrative of the list is part of the attested content of the document.
In a dynamic environment, the narrative content of a list will be limited to the version of the linked resources at the time the list was last updated. It may be even earlier if the narrative isn't updated to reflect the most recent version of all referenced resources at each update. Best practice for 'working' lists is to update the narrative to reflect the most recent content of all list elements each time the list is revised. Lists should therefore not be relied on as a real-time view of the referenced content. There are a few possible approaches to work around this issue:
If a list is empty, there could be several different reasons why this is so. For example:
Given these possibilities - especially the common and significant first case - for many kinds of lists, source systems SHOULD provide an empty reason if the list is empty. Because of the importance of the first case, the special value "nil-known" should be used when there are no (significant) entries in this context of care. Note that this concept is sometimes described differently, such as "patient denies taking medications", or "patient was unable to identify any relevant medical history".
When receiving a list, systems should not assume that the list is complete (some entries may have been withheld for a variety of reasons), unless there are specific trading partner arrangements in place or, if the list is empty, that there are actually nil known, unless the "nil-known" code is present.
If a list is empty, the narrative should contain text equivalent to the empty reason.
Note that there are also many kinds of lists that can be empty with no need for an empty reason (example)
empty-reason | Why list is empty | List.emptyReason |
item | Actual entry | List.entry.item |
notes | The annotation - text content (as markdown) | List.note.text |
source | Who and/or what defined the list contents (aka Author) | List.source |
status | current | retired | entered-in-error | List.status |
subject | If all resources have the same subject | List.subject |
title | Descriptive name for the list | List.title |