Release 4 Code System

Biomedical Research and Regulation Work Group Maturity Level: 1Trial Use Use Context: Any

This is a code system defined by the FHIR project.


Defining URL:

Indicates the progression of a study subject through a study.

Committee:Biomedical Research and Regulation Work Group
OID:2.16.840.1.113883.4.642.4.830 (for OID based terminology systems)
Source ResourceXML / JSON

This Code system is used in the following value sets:

Indicates the progression of a study subject through a study.

This code system defines the following codes:

candidate CandidateAn identified person that can be considered for inclusion in a study.
eligible EligibleA person that has met the eligibility criteria for inclusion in a study.
follow-up Follow-upA person is no longer receiving study intervention and/or being evaluated with tests and procedures according to the protocol, but they are being monitored on a protocol-prescribed schedule.
ineligible IneligibleA person who did not meet one or more criteria required for participation in a study is considered to have failed screening or is ineligible for the study.
not-registered Not RegisteredA person for whom registration was not completed.
off-study Off-studyA person that has ended their participation on a study either because their treatment/observation is complete or through not responding, withdrawal, non-compliance and/or adverse event.
on-study On-studyA person that is enrolled or registered on a study.
on-study-intervention On-study-interventionThe person is receiving the treatment or participating in an activity (e.g. yoga, diet, etc.) that the study is evaluating.
on-study-observation On-study-observationThe subject is being evaluated via tests and assessments according to the study calendar, but is not receiving any intervention. Note that this state is study-dependent and might not exist in all studies. A synonym for this is "short-term follow-up".
pending-on-study Pending on-studyA person is pre-registered for a study.
potential-candidate Potential CandidateA person that is potentially eligible for participation in the study.
screening ScreeningA person who is being evaluated for eligibility for a study.
withdrawn WithdrawnThe person has withdrawn their participation in the study before registration.


See the full registry of code systems defined as part of FHIR.

Explanation of the columns that may appear on this page:

LevelA few code lists that FHIR defines are hierarchical - each code is assigned a level. See Code System for further information.
SourceThe source of the definition of the code (when the value set draws in codes defined elsewhere)
CodeThe code (used as the code in the resource instance). If the code is in italics, this indicates that the code is not selectable ('Abstract')
DisplayThe display (used in the display element of a Coding). If there is no display, implementers should not simply display the code, but map the concept into their application
DefinitionAn explanation of the meaning of the concept
CommentsAdditional notes about how to use the code