> ## Documentation Index
> Fetch the complete documentation index at: https://docs.corti.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Condition resource group

> Learn which diagnoses, problems, symptoms, and signs become FHIR R4 Condition resources, and which fields the Corti API fills

A Condition resource records one diagnosis, problem, symptom, or sign that concerns the clinician. The endpoint creates one Condition per condition it finds in the note, coded with [SNOMED CT](https://www.snomed.org/). The resource follows the [FHIR R4 Condition](https://hl7.org/fhir/R4/condition.html) specification, and each field name below links to its R4 definition.

## What becomes a Condition

| Note says | Condition `code` |
| - | - |
| "Type 2 diabetes, poorly controlled" | `44054006` Type 2 diabetes mellitus |
| "Possible community-acquired pneumonia" | `385093006` Community acquired pneumonia, with `verificationStatus: provisional` |
| "Left knee pain for three weeks" | `1003722009` Pain of knee region, with `bodySite` left knee |
| "History of appendicitis" | `74400008` Appendicitis, with `clinicalStatus: resolved` |

Some things in a note look like conditions but belong to other resource groups:

| Note says | Resource group | Why |
| - | - | - |
| "Penicillin allergy" | [AllergyIntolerance](https://docs.corti.ai/fhir/resource-groups/allergy-intolerance.md) | Allergies need reaction and criticality fields that a Condition does not have. |
| "Father had a myocardial infarction" | [FamilyMemberHistory](https://docs.corti.ai/fhir/resource-groups/family-member-history.md) | The condition belongs to a relative, not the patient. |
| "No murmurs on auscultation" | [Observation](https://docs.corti.ai/fhir/resource-groups/observation.md) | An exam finding is an observation, not a diagnosis. |

## Negated, past, and uncertain conditions

The `code` always names the condition itself, in positive form. The endpoint is built to avoid negated or historic codes, such as `86699002` Afebrile or `399211009` History of myocardial infarction. The status fields carry that meaning instead:

| Note says | `code` | `clinicalStatus` | `verificationStatus` |
| - | - | - | - |
| "Fever since yesterday" | `386661006` Fever | `active` | |
| "Afebrile" | `386661006` Fever | | `refuted` |
| "Denies fever or chills" | `386661006` Fever, and a second Condition for `43724002` Chill | | `refuted` on both |
| "PMH: MI in 2015" | `22298006` Myocardial infarction | `resolved` | `confirmed` |
| "Suspected pneumonia" | `233604007` Pneumonia | | `provisional` |

A refuted Condition means the patient does **not** have the condition. Check `verificationStatus` and `clinicalStatus` before you treat a Condition as a current diagnosis. [Codes are positive](https://docs.corti.ai/fhir/how-it-works.md#codes-are-positive) explains why the endpoint works this way.

## Fields

The endpoint fills a field only when the note supports it, and leaves out every empty field.

| Field | Type | What it holds | Example from a note |
| - | - | - | - |
| [`code`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.code) | [CodeableConcept](https://docs.corti.ai/fhir/datatypes.md#codeableconcept) | The condition, in SNOMED CT (a disorder, finding, or event) | "asthma" → `195967001` Asthma |
| [`clinicalStatus`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.clinicalStatus) | [CodeableConcept](https://docs.corti.ai/fhir/datatypes.md#codeableconcept) | `active`, `recurrence`, `relapse`, `inactive`, `remission`, `resolved`, or `unknown`. `unknown` is not in the R4 value set, so map it before you import into a strict R4 server. See [How the response meets FHIR R4](https://docs.corti.ai/fhir/how-it-works.md#how-the-response-meets-fhir-r4). Defaults to `active`, or to `inactive` when the note states that the condition ended, because R4 does not allow an ended condition to be active. Left out when `verificationStatus` is `entered-in-error`. See the [R4 value set](https://hl7.org/fhir/R4/valueset-condition-clinical.html). | "resolved after antibiotics" → `resolved` |
| [`verificationStatus`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.verificationStatus) | [CodeableConcept](https://docs.corti.ai/fhir/datatypes.md#codeableconcept) | `unconfirmed`, `provisional`, `differential`, `confirmed`, `refuted`, or `entered-in-error`. See the [R4 value set](https://hl7.org/fhir/R4/valueset-condition-ver-status.html). | "rule out PE" → `differential` |
| [`category`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.category) | [CodeableConcept](https://docs.corti.ai/fhir/datatypes.md#codeableconcept) list | `problem-list-item` or `encounter-diagnosis`. See the [R4 value set](https://hl7.org/fhir/R4/valueset-condition-category.html). | "known hypertension" → `problem-list-item` |
| [`severity`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.severity) | [CodeableConcept](https://docs.corti.ai/fhir/datatypes.md#codeableconcept) | SNOMED CT `255604002` Mild, `6736007` Moderate, or `24484000` Severe. See the [R4 value set](https://hl7.org/fhir/R4/valueset-condition-severity.html). | "severe asthma" → Severe |
| [`bodySite`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.bodySite) | [CodeableConcept](https://docs.corti.ai/fhir/datatypes.md#codeableconcept) list | The body structure, in SNOMED CT | "left knee pain" → left knee structure |
| [`onsetDateTime`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.onset_x_) or [`onsetString`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.onset_x_) | [dateTime](https://docs.corti.ai/fhir/datatypes.md#primitive-types) or [string](https://docs.corti.ai/fhir/datatypes.md#primitive-types) | When it started. A date only when the note states one. | "since 2018" → `onsetDateTime: "2018"` |
| [`abatementDateTime`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.abatement_x_) or [`abatementString`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.abatement_x_) | [dateTime](https://docs.corti.ai/fhir/datatypes.md#primitive-types) or [string](https://docs.corti.ai/fhir/datatypes.md#primitive-types) | When it ended | "resolved last week" → `abatementString: "last week"` |
| [`stage`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.stage) | list of `{ summary, type }` | The stage or grade, as text | "stage II" → `summary.text: "stage II"` |
| [`evidence`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.evidence) | list of `{ code }`, with [CodeableConcept](https://docs.corti.ai/fhir/datatypes.md#codeableconcept) text | Supporting evidence, as text | "confirmed by CT" |
| [`asserter`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.asserter) | [Reference](https://docs.corti.ai/fhir/datatypes.md#reference) | Who made the diagnosis, as `display` text | "per cardiology" |
| [`note`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.note) | list of [Annotation](https://docs.corti.ai/fhir/datatypes.md#annotation) | Extra context that fits no other field | |
| [`subject`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.subject) | [Reference](https://docs.corti.ai/fhir/datatypes.md#reference) | The Patient of the Bundle | |
| [`encounter`](https://hl7.org/fhir/R4/condition-definitions.html#Condition.encounter) | [Reference](https://docs.corti.ai/fhir/datatypes.md#reference) | The Encounter of the note | |
| [`extension`](https://hl7.org/fhir/R4/extensibility.html#Extension) | list of [Extension](https://docs.corti.ai/fhir/datatypes.md#extension) | [Mentions and alternatives](https://docs.corti.ai/fhir/how-it-works.md#every-value-points-back-to-the-note) | |

## Codes the endpoint can assign

The endpoint only searches a fixed part of each coding system for each field. A code outside that part never appears, and a [filter](https://docs.corti.ai/fhir/filter-reference.md#how-filters-combine) can only narrow the part further, never widen it. [Codes come from a fixed scope](https://docs.corti.ai/fhir/how-it-works.md#codes-come-from-a-fixed-scope) explains why.

| Field | Coding system | Allowed codes | Example |
| - | - | - | - |
| `code` | SNOMED CT | Semantic tag `disorder`, `finding`, or `event` | `195967001` Asthma (disorder), `29857009` Chest pain (finding) |
| `bodySite` | SNOMED CT | `442083009` Anatomical or acquired body structure, and its descendants | `39607008` Lung structure |
| `severity` | SNOMED CT | A fixed list: `255604002` Mild, `6736007` Moderate, `24484000` Severe | |
| `clinicalStatus`, `verificationStatus`, `category` | HL7 code systems | The FHIR value sets listed under [Fields](#fields) | |

A procedure code, such as `80146002` Appendectomy, can never become a Condition `code`, because its semantic tag is `procedure`.

## Example

```text theme={null}
Mild asthma since 2018, currently well controlled. Lungs clear.
```

> [tab] Simplified
>
> | Field | Value |
> | - | - |
> | `code` | `195967001` Asthma |
> | `clinicalStatus` | `active` |
> | `category` | `problem-list-item` |
> | `severity` | `255604002` Mild |
> | `onsetDateTime` | `2018` |

> [tab] JSON
>
> ```json theme={null}
> {
>   "extension": [
>     {
>       "url": "https://docs.corti.ai/fhir/StructureDefinition/mention",
>       "extension": [
>         { "url": "field", "valueString": "code" },
>         {
>           "url": "evidence",
>           "extension": [
>             { "url": "start", "valueInteger": 5 },
>             { "url": "end", "valueInteger": 11 },
>             { "url": "text", "valueString": "asthma" }
>           ]
>         }
>       ]
>     },
>     {
>       "url": "https://docs.corti.ai/fhir/StructureDefinition/mention",
>       "extension": [
>         { "url": "field", "valueString": "severity" },
>         {
>           "url": "evidence",
>           "extension": [
>             { "url": "start", "valueInteger": 0 },
>             { "url": "end", "valueInteger": 4 },
>             { "url": "text", "valueString": "Mild" }
>           ]
>         }
>       ]
>     }
>   ],
>   "resourceType": "Condition",
>   "id": "3b3921ad-2029-560e-b13c-0505d69698bd",
>   "clinicalStatus": {
>     "coding": [
>       {
>         "system": "http://terminology.hl7.org/CodeSystem/condition-clinical",
>         "code": "active",
>         "display": "Active"
>       }
>     ],
>     "text": "Active"
>   },
>   "category": [
>     {
>       "coding": [
>         {
>           "system": "http://terminology.hl7.org/CodeSystem/condition-category",
>           "code": "problem-list-item",
>           "display": "Problem List Item"
>         }
>       ],
>       "text": "Problem List Item"
>     }
>   ],
>   "severity": {
>     "coding": [
>       {
>         "system": "http://snomed.info/sct",
>         "code": "255604002",
>         "display": "Mild"
>       }
>     ],
>     "text": "Mild"
>   },
>   "code": {
>     "coding": [
>       {
>         "system": "http://snomed.info/sct",
>         "code": "195967001",
>         "display": "Asthma"
>       }
>     ],
>     "text": "Asthma"
>   },
>   "subject": { "reference": "urn:uuid:b49ecda5-92db-5325-a7a9-f82c71500bad", "type": "Patient" },
>   "encounter": {
>     "reference": "urn:uuid:29543af8-9ec2-528e-8a3b-1e891822d99d",
>     "type": "Encounter",
>     "identifier": {
>       "system": "http://corti.app/fhir/identifier/encounter",
>       "value": "enc-88213"
>     }
>   },
>   "onsetDateTime": "2018"
> }
> ```

"Lungs clear" does not become a Condition. It becomes an exam [Observation](https://docs.corti.ai/fhir/resource-groups/observation.md).

## Next steps

> [card] [Observation resource group](https://docs.corti.ai/fhir/resource-groups/observation.md)
>
> Learn how vital signs, lab results, and exam findings look in FHIR.

> [card] [Filter FHIR resources](https://docs.corti.ai/fhir/filtering.md)
>
> Produce only problem-list Conditions, or restrict Condition codes.


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