---
type: "search-params"
title: "ResearchSubject Search Parameters"
resource: "ResearchSubject"
---
# ResearchSubject Search Parameters

<a id="date"></a>

## date
**Description:** Start and end of participation

**Type:** date

**Expression:** ResearchSubject.period

**Path:** ResearchSubject.period

**Standards Status:** normative

**URL:** http://hl7.org/fhir/build/SearchParameter/ResearchSubject-date


<a id="identifier"></a>

## identifier
**Description:** Business Identifier for research subject in a study

**Type:** token

**Expression:** ResearchSubject.identifier

**Path:** ResearchSubject.identifier

**Standards Status:** normative

**URL:** http://hl7.org/fhir/build/SearchParameter/ResearchSubject-identifier


<a id="subject"></a>

## subject
**Description:** Who or what is part of study

**Type:** reference

**Expression:** ResearchSubject.subject

**Path:** ResearchSubject.subject

**Standards Status:** normative

**URL:** http://hl7.org/fhir/build/SearchParameter/ResearchSubject-subject


<a id="patient"></a>

## patient
**Description:** Who or what is part of study

**Type:** reference

**Expression:** ResearchSubject.subject.where(resolve() is Patient)

**Path:** ResearchSubject.subject

**Standards Status:** normative

**URL:** http://hl7.org/fhir/build/SearchParameter/ResearchSubject-patient


<a id="subject_state"></a>

## subject_state
**Description:** candidate | in-prescreening | in-screening | eligible | ineligible | on-study | on-study-intervention | in-follow-up | off-study

**Type:** token

**Expression:** ResearchSubject.subjectState.code

**Path:** ResearchSubject.subjectState.code

**Standards Status:** normative

**URL:** http://hl7.org/fhir/build/SearchParameter/ResearchSubject-state


<a id="status"></a>

## status
**Description:** draft | active | retired | unknown

**Type:** token

**Expression:** ResearchSubject.status

**Path:** ResearchSubject.status

**Standards Status:** normative

**URL:** http://hl7.org/fhir/build/SearchParameter/ResearchSubject-status


<a id="study"></a>

## study
**Description:** Study subject is part of

**Type:** reference

**Expression:** ResearchSubject.study

**Path:** ResearchSubject.study

**Standards Status:** normative

**URL:** http://hl7.org/fhir/build/SearchParameter/ResearchSubject-study