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

# ResearchSubject

> A physical entity which is the primary unit of operational and/or administrative interest in a study.

## Properties

| Name        | Required | Type                                                                   | Description                                                                                                                                                                                           |
| ----------- | -------- | ---------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| identifier  | No       | [Identifier](/medical-api/fhir/data-types/identifier)\[]               | Business Identifier for research subject in a study                                                                                                                                                   |
| status      | Yes      | code                                                                   | candidate / eligible / follow-up / ineligible / not-registered / off-study / on-study / on-study-intervention / on-study-observation / pending-on-study / potential-candidate / screening / withdrawn |
| period      | No       | [Period](/medical-api/fhir/data-types/period)                          | Start and end of participation                                                                                                                                                                        |
| study       | Yes      | Reference\<[ResearchStudy](/medical-api/fhir/resources/researchstudy)> | Study subject is part of                                                                                                                                                                              |
| individual  | Yes      | Reference\<[Patient](/medical-api/fhir/resources/patient)>             | Who is part of study                                                                                                                                                                                  |
| assignedArm | No       | string                                                                 | What path should be followed                                                                                                                                                                          |
| actualArm   | No       | string                                                                 | What path was followed                                                                                                                                                                                |
| consent     | No       | Reference\<[Consent](/medical-api/fhir/resources/consent)>             | Agreement to participate in study                                                                                                                                                                     |

## Search Parameters

| Name       | Type      | Description                                                                                                                                                                                           | Expression                 |
| ---------- | --------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------- |
| date       | date      | Start and end of participation                                                                                                                                                                        | ResearchSubject.period     |
| identifier | token     | Business Identifier for research subject in a study                                                                                                                                                   | ResearchSubject.identifier |
| individual | reference | Who is part of study                                                                                                                                                                                  | ResearchSubject.individual |
| patient    | reference | Who is part of study                                                                                                                                                                                  | ResearchSubject.individual |
| status     | token     | candidate / eligible / follow-up / ineligible / not-registered / off-study / on-study / on-study-intervention / on-study-observation / pending-on-study / potential-candidate / screening / withdrawn | ResearchSubject.status     |
| study      | reference | Study subject is part of                                                                                                                                                                              | ResearchSubject.study      |

## Inherited Properties

| Name              | Required | Type                                                   | Description                                            |
| ----------------- | -------- | ------------------------------------------------------ | ------------------------------------------------------ |
| id                | No       | string                                                 | Logical id of this artifact                            |
| meta              | No       | [Meta](/medical-api/fhir/data-types/meta)              | Metadata about the resource                            |
| implicitRules     | No       | uri                                                    | A set of rules under which this content was created    |
| language          | No       | code                                                   | Language of the resource content                       |
| text              | No       | [Narrative](/medical-api/fhir/data-types/narrative)    | Text summary of the resource, for human interpretation |
| contained         | No       | Resource\[]                                            | Contained, inline Resources                            |
| extension         | No       | [Extension](/medical-api/fhir/data-types/extension)\[] | Additional content defined by implementations          |
| modifierExtension | No       | [Extension](/medical-api/fhir/data-types/extension)\[] | Extensions that cannot be ignored                      |

To view the FHIR specification for this resource, see [ResearchSubject](https://www.hl7.org/fhir/StructureDefinition/ResearchSubject).