{ "resourceType": "StructureDefinition", "id": "encounter-abnormal", "url": "https://fhir.apps.health/StructureDefinition/encounter-abnormal", "name": "EncounterAbnormal", "title": "Encounter Abnormal Extension", "status": "draft", "date": "2026-09-14", "publisher": "WELLSTAR Technologies Corp.", "description": "Marks an encounter as abnormal: what this visit produced warrants somebody looking at it.\n\n**One flag on the encounter, not a finding about any one result.** R4 offers no element for this --\n`diagnosis` names conditions and `status` names where the visit got to -- and it is deliberately\ncoarser than an `Observation.interpretation` code, which answers the same question for a single\nmeasurement. This exists so a workflow can find the encounter at all without re-reading everything\nfiled under it. A consumer wanting to know WHICH result was abnormal must read the results.\n\n**Setting it has a consequence on a different resource.** A periodic review walks orders carrying\nthe [`action-on-abnormal`](StructureDefinition-action-on-abnormal.md) instruction, follows each\norder to its appointments and each appointment to its encounters, and where any of those encounters\ncarries this flag as `true` it flags the ORDER as needing review: a system note is added to the\norder, and every task filed against the order is given needs-review business status. Write `true`\nonly where that outcome is intended.\n\n**Absent and `false` mean the same thing.** The review treats a missing extension, a `false` value\nand an unreadable one alike, and raises no error on any of them. `false` exists so the flag can be\ncleared in place rather than by removing the extension.\n\n**At most one per encounter.** A reader meeting more than one should take the first.\n\n**Nothing writes this today.** No writer in Nexus EMR produces the marker, so the review described\nabove currently never fires on it and every encounter in the estate reads as not abnormal; that is\ntracked as FHIR-387. It is declared because the reader is live: an encounter carrying `true` from any\nsource WILL be acted on as described. Treat this as an input contract, not as a field to expect in\ndata Nexus EMR hands you.\n\n**MIGRATION.** The reader in Nexus EMR looks for this extension today at\n`http://services.well.com/fhir/encounter/is-abnormal`, an address on a host this specification does\nnot govern, minted in application code before the guide declared the extension; the move onto the\ncanonical declared here is tracked as FHIR-371. Write the canonical; expect both until the migration\ncompletes, and match both addresses exactly rather than deriving one from the other -- they share no\nfinal segment, so a rule built on the last path element reaches neither from the other.", "fhirVersion": "4.0.1", "mapping": [ { "identity": "rim", "uri": "http://hl7.org/v3", "name": "RIM Mapping" } ], "kind": "complex-type", "abstract": false, "context": [ { "type": "element", "expression": "Encounter" } ], "type": "Extension", "baseDefinition": "http://hl7.org/fhir/StructureDefinition/Extension", "derivation": "constraint", "snapshot": { "element": [ { "id": "Extension", "path": "Extension", "short": "Encounter Abnormal Extension", "definition": "Marks an encounter as abnormal: what this visit produced warrants somebody looking at it.\n\n**One flag on the encounter, not a finding about any one result.** R4 offers no element for this --\n`diagnosis` names conditions and `status` names where the visit got to -- and it is deliberately\ncoarser than an `Observation.interpretation` code, which answers the same question for a single\nmeasurement. This exists so a workflow can find the encounter at all without re-reading everything\nfiled under it. A consumer wanting to know WHICH result was abnormal must read the results.\n\n**Setting it has a consequence on a different resource.** A periodic review walks orders carrying\nthe [`action-on-abnormal`](StructureDefinition-action-on-abnormal.md) instruction, follows each\norder to its appointments and each appointment to its encounters, and where any of those encounters\ncarries this flag as `true` it flags the ORDER as needing review: a system note is added to the\norder, and every task filed against the order is given needs-review business status. Write `true`\nonly where that outcome is intended.\n\n**Absent and `false` mean the same thing.** The review treats a missing extension, a `false` value\nand an unreadable one alike, and raises no error on any of them. `false` exists so the flag can be\ncleared in place rather than by removing the extension.\n\n**At most one per encounter.** A reader meeting more than one should take the first.\n\n**Nothing writes this today.** No writer in Nexus EMR produces the marker, so the review described\nabove currently never fires on it and every encounter in the estate reads as not abnormal; that is\ntracked as FHIR-387. It is declared because the reader is live: an encounter carrying `true` from any\nsource WILL be acted on as described. Treat this as an input contract, not as a field to expect in\ndata Nexus EMR hands you.\n\n**MIGRATION.** The reader in Nexus EMR looks for this extension today at\n`http://services.well.com/fhir/encounter/is-abnormal`, an address on a host this specification does\nnot govern, minted in application code before the guide declared the extension; the move onto the\ncanonical declared here is tracked as FHIR-371. Write the canonical; expect both until the migration\ncompletes, and match both addresses exactly rather than deriving one from the other -- they share no\nfinal segment, so a rule built on the last path element reaches neither from the other.", "min": 0, "max": "*", "base": { "path": "Extension", "min": 0, "max": "*" }, "condition": [ "ele-1" ], "constraint": [ { "key": "ele-1", "severity": "error", "human": "All FHIR elements must have a @value or children", "expression": "hasValue() or (children().count() > id.count())", "xpath": "@value|f:*|h:div", "source": "http://hl7.org/fhir/StructureDefinition/Element" }, { "key": "ext-1", "severity": "error", "human": "Must have either extensions or value[x], not both", "expression": "extension.exists() != value.exists()", "xpath": "exists(f:extension)!=exists(f:*[starts-with(local-name(.), 'value')])" } ], "isModifier": false, "mapping": [ { "identity": "rim", "map": "n/a" }, { "identity": "rim", "map": "N/A" } ] }, { "id": "Extension.id", "path": "Extension.id", "representation": [ "xmlAttr" ], "short": "Unique id for inter-element referencing", "definition": "Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.", "min": 0, "max": "1", "base": { "path": "Element.id", "min": 0, "max": "1" }, "type": [ { "code": "http://hl7.org/fhirpath/System.String", "extension": [ { "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type", "valueUrl": "string" } ] } ], "isModifier": false, "isSummary": false, "mapping": [ { "identity": "rim", "map": "n/a" } ] }, { "id": "Extension.extension", "path": "Extension.extension", "slicing": { "discriminator": [ { "type": "value", "path": "url" } ], "description": "Extensions are always sliced by (at least) url", "rules": "open" }, "short": "Additional content defined by implementations", "definition": "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.", "comment": "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.", "alias": [ "extensions", "user content" ], "min": 0, "max": "0", "base": { "path": "Element.extension", "min": 0, "max": "*" }, "type": [ { "code": "Extension" } ], "constraint": [ { "key": "ele-1", "severity": "error", "human": "All FHIR elements must have a @value or children", "expression": "hasValue() or (children().count() > id.count())", "xpath": "@value|f:*|h:div", "source": "http://hl7.org/fhir/StructureDefinition/Element" }, { "key": "ext-1", "severity": "error", "human": "Must have either extensions or value[x], not both", "expression": "extension.exists() != value.exists()", "xpath": "exists(f:extension)!=exists(f:*[starts-with(local-name(.), \"value\")])", "source": "http://hl7.org/fhir/StructureDefinition/Extension" } ], "isModifier": false, "isSummary": false, "mapping": [ { "identity": "rim", "map": "n/a" } ] }, { "id": "Extension.url", "path": "Extension.url", "representation": [ "xmlAttr" ], "short": "identifies the meaning of the extension", "definition": "Source of the definition for the extension code - a logical name or a URL.", "comment": "The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.", "min": 1, "max": "1", "base": { "path": "Extension.url", "min": 1, "max": "1" }, "type": [ { "code": "http://hl7.org/fhirpath/System.String", "extension": [ { "url": "http://hl7.org/fhir/StructureDefinition/structuredefinition-fhir-type", "valueUrl": "uri" } ] } ], "fixedUri": "https://fhir.apps.health/StructureDefinition/encounter-abnormal", "isModifier": false, "isSummary": false, "mapping": [ { "identity": "rim", "map": "N/A" } ] }, { "id": "Extension.value[x]", "path": "Extension.value[x]", "short": "True when this encounter is marked abnormal", "definition": "`true` when this encounter is marked abnormal and a review of the orders it answers should surface it. `false` means not abnormal and carries nothing an absent extension does not; it exists so the flag can be cleared in place.", "min": 1, "max": "1", "base": { "path": "Extension.value[x]", "min": 0, "max": "1" }, "type": [ { "code": "boolean" } ], "constraint": [ { "key": "ele-1", "severity": "error", "human": "All FHIR elements must have a @value or children", "expression": "hasValue() or (children().count() > id.count())", "xpath": "@value|f:*|h:div", "source": "http://hl7.org/fhir/StructureDefinition/Element" } ], "mustSupport": true, "isModifier": false, "isSummary": false, "mapping": [ { "identity": "rim", "map": "N/A" } ] } ] }, "differential": { "element": [ { "id": "Extension", "path": "Extension", "short": "Encounter Abnormal Extension", "definition": "Marks an encounter as abnormal: what this visit produced warrants somebody looking at it.\n\n**One flag on the encounter, not a finding about any one result.** R4 offers no element for this --\n`diagnosis` names conditions and `status` names where the visit got to -- and it is deliberately\ncoarser than an `Observation.interpretation` code, which answers the same question for a single\nmeasurement. This exists so a workflow can find the encounter at all without re-reading everything\nfiled under it. A consumer wanting to know WHICH result was abnormal must read the results.\n\n**Setting it has a consequence on a different resource.** A periodic review walks orders carrying\nthe [`action-on-abnormal`](StructureDefinition-action-on-abnormal.md) instruction, follows each\norder to its appointments and each appointment to its encounters, and where any of those encounters\ncarries this flag as `true` it flags the ORDER as needing review: a system note is added to the\norder, and every task filed against the order is given needs-review business status. Write `true`\nonly where that outcome is intended.\n\n**Absent and `false` mean the same thing.** The review treats a missing extension, a `false` value\nand an unreadable one alike, and raises no error on any of them. `false` exists so the flag can be\ncleared in place rather than by removing the extension.\n\n**At most one per encounter.** A reader meeting more than one should take the first.\n\n**Nothing writes this today.** No writer in Nexus EMR produces the marker, so the review described\nabove currently never fires on it and every encounter in the estate reads as not abnormal; that is\ntracked as FHIR-387. It is declared because the reader is live: an encounter carrying `true` from any\nsource WILL be acted on as described. Treat this as an input contract, not as a field to expect in\ndata Nexus EMR hands you.\n\n**MIGRATION.** The reader in Nexus EMR looks for this extension today at\n`http://services.well.com/fhir/encounter/is-abnormal`, an address on a host this specification does\nnot govern, minted in application code before the guide declared the extension; the move onto the\ncanonical declared here is tracked as FHIR-371. Write the canonical; expect both until the migration\ncompletes, and match both addresses exactly rather than deriving one from the other -- they share no\nfinal segment, so a rule built on the last path element reaches neither from the other." }, { "id": "Extension.extension", "path": "Extension.extension", "max": "0" }, { "id": "Extension.url", "path": "Extension.url", "fixedUri": "https://fhir.apps.health/StructureDefinition/encounter-abnormal" }, { "id": "Extension.value[x]", "path": "Extension.value[x]", "short": "True when this encounter is marked abnormal", "definition": "`true` when this encounter is marked abnormal and a review of the orders it answers should surface it. `false` means not abnormal and carries nothing an absent extension does not; it exists so the flag can be cleared in place.", "min": 1, "type": [ { "code": "boolean" } ], "mustSupport": true } ] } }