The CSR (Clinical Study Registration) segment records the enrollment of an individual patient into a sponsored clinical study. It binds a patient to a study sponsor identifier, captures the registering institution, and timestamps the moment of registration along with consent, eligibility, randomization, and study-exit details. CSR is the anchor segment of a patient's clinical-study record and is typically the first of the clinical-study group followed by CSP and CSS.
Purpose
CSR exists to assert that a specific patient has been registered into a specific clinical study under a specific sponsor. It conveys the administrative and protocol identifiers needed to track a subject across the study lifecycle: the sponsor's study identifier, the sponsor's patient identifier, the registering and authorizing providers, consent and eligibility status, randomization arm and stratum, and the date and reason a patient ended the study. Downstream systems use CSR to reconcile subject enrollment against a study protocol and to drive evaluability reporting.
Used in
CSR carries patient clinical-study registration data inside CSU (Unsolicited Study Data) messages. Within a CSU message the clinical-study group normally appears after PID, with CSR establishing the registration, CSP describing the study phase, and CSS describing the data-collection schedule.
- CSU — Unsolicited Study Data: see /academy/hl7/messages/csu
Field-by-field reference
Source: HAPI HL7v2 v2.5.1 javadocs (CSR.html). Length is shown as —; Required and Table # are taken from the HL7 v2.5.1 standard where well-established.
| Seq | Name | Data Type | Length | Req | Repeat | Table # | Description |
|---|---|---|---|---|---|---|---|
| CSR-1 | Sponsor Study ID | ei | — | R | — | — | Sponsor's primary identifier for the study |
| CSR-2 | Alternate Study ID | ei | — | O | — | — | Secondary or local identifier for the study |
| CSR-3 | Institution Registering the Patient | ce | — | O | — | — | Facility that registered the patient |
| CSR-4 | Sponsor Patient ID | cx | — | O | — | — | Sponsor's identifier for the study patient |
| CSR-5 | Alternate Patient ID - CSR | cx | — | O | — | — | Secondary or local patient identifier |
| CSR-6 | Date/Time Of Patient Study Registration | ts | — | O | — | — | When the patient was registered into study |
| CSR-7 | Person Performing Study Registration | xcn | — | O | Y | — | Individual who performed the registration |
| CSR-8 | Study Authorizing Provider | xcn | — | O | Y | — | Provider authorizing study participation |
| CSR-9 | Date/time Patient Study Consent Signed | ts | — | O | — | — | When the patient signed study consent |
| CSR-10 | Patient Study Eligibility Status | ce | — | O | — | — | Eligibility determination for the study |
| CSR-11 | Study Randomization Date/time | ts | — | O | Y | — | When the patient was randomized |
| CSR-12 | Randomized Study Arm | ce | — | O | Y | — | Treatment arm assigned at randomization |
| CSR-13 | Stratum for Study Randomization | ce | — | O | Y | — | Stratification group for randomization |
| CSR-14 | Patient Evaluability Status | ce | — | O | — | — | Whether patient data is evaluable |
| CSR-15 | Date/time Ended Study | ts | — | O | — | — | When the patient ended the study |
| CSR-16 | Reason Ended Study | ce | — | O | — | — | Coded reason the patient ended study |
Most-used fields
- CSR-1 Sponsor Study ID: the required key that ties every clinical-study segment to one protocol.
- CSR-4 Sponsor Patient ID: the sponsor-assigned subject identifier used for cross-system reconciliation.
- CSR-6 Date/Time Of Patient Study Registration: the enrollment timestamp that opens the subject record.
- CSR-10 Patient Study Eligibility Status: drives whether the subject contributes to analysis cohorts.
- CSR-12 Randomized Study Arm: the assigned treatment arm for randomized trials.
- CSR-15 / CSR-16 Date and Reason Ended Study: close out the subject and explain discontinuation.
Version differences (2.3 to 2.8.2)
- The clinical-study segments (CSR, CSP, CSS) were introduced in HL7 v2.3 to support the CSU unsolicited study-data message.
- Through 2.3.1 and 2.4 the field roster of CSR remained stable, with randomization and evaluability fields present from the outset.
- In 2.5 and 2.5.1 the coded fields continued to use CE; this page reflects the 2.5.1 structure as published in the HAPI javadocs.
- From 2.6 onward, many coded fields across the standard migrated toward CWE; implementers targeting 2.7 through 2.8.2 should confirm whether a partner expresses CSR coded fields as CE or CWE.
- No fields have been removed from CSR across these releases; differences are primarily data-type normalization rather than field additions.
Common mistakes
- Omitting CSR-1 Sponsor Study ID, which the standard requires; without it the segment cannot be tied to a protocol.
- Confusing CSR-4 Sponsor Patient ID with the PID-3 patient identifier; they serve different identity domains.
- Sending only one occurrence of CSR-7 or CSR-8 when multiple authorizing providers exist; both fields repeat.
- Treating CSR-12 Randomized Study Arm as free text instead of a coded value.
- Populating CSR-15 Date/time Ended Study without CSR-16 Reason Ended Study, leaving discontinuation unexplained.
- Assuming CE components are interchangeable with CWE on partners running 2.7 or later.
Examples
Minimal CSR (required identifier and registration timestamp):
CSR|STUDY2024-ONC-17^^^SPONSOR^STUDY|||PT-90031^^^SPONSOR^MR||20260601103000
Fully populated CSR:
CSR|STUDY2024-ONC-17^^^SPONSOR^STUDY|ALT-ONC-17^^^SITE^LOCAL|RH001^Riverside Research Hospital^L|PT-90031^^^SPONSOR^MR|LOC-5521^^^SITE^MR|20260601103000|72811^Reyes^Maria^^^Dr^^^SPONSOR^L|44102^Okafor^Daniel^^^Dr^^^SPONSOR^L|20260530090000|ELIG^Eligible^L|20260601110000|ARM-B^Treatment Arm B^L|STRAT2^Stratum 2 Age 50-65^L|EVAL^Evaluable^L|20260612160000|COMPLETED^Protocol Completed^L
Annotated breakdown:
CSR-1 Sponsor Study ID ............ STUDY2024-ONC-17 (sponsor study domain)
CSR-2 Alternate Study ID .......... ALT-ONC-17 (local site identifier)
CSR-3 Institution Registering ..... RH001 Riverside Research Hospital
CSR-4 Sponsor Patient ID .......... PT-90031 (sponsor MR domain)
CSR-5 Alternate Patient ID ........ LOC-5521 (site MR domain)
CSR-6 Date/Time Registration ...... 2026-06-01 10:30:00
CSR-7 Person Performing Reg ....... Dr Maria Reyes (id 72811)
CSR-8 Study Authorizing Provider .. Dr Daniel Okafor (id 44102)
CSR-9 Consent Signed .............. 2026-05-30 09:00:00
CSR-10 Eligibility Status .......... ELIG Eligible
CSR-11 Randomization Date/time ..... 2026-06-01 11:00:00
CSR-12 Randomized Study Arm ........ ARM-B Treatment Arm B
CSR-13 Stratum ..................... STRAT2 Stratum 2 Age 50-65
CSR-14 Evaluability Status ......... EVAL Evaluable
CSR-15 Date/time Ended Study ....... 2026-06-12 16:00:00
CSR-16 Reason Ended Study .......... COMPLETED Protocol Completed
In context, inside a CSU unsolicited study-data message after PID:
MSH|^~&|EDC|SPONSOR|REG|SITE|20260601103500||CSU^C09^CSU_C09|MSG00451|P|2.5.1
PID|1||PT-90031^^^SPONSOR^MR||Doe^Jane^A||19710204|F
CSR|STUDY2024-ONC-17^^^SPONSOR^STUDY|||PT-90031^^^SPONSOR^MR||20260601103000|72811^Reyes^Maria^^^Dr|||ELIG^Eligible^L
A second in-context excerpt showing a study-exit registration:
MSH|^~&|EDC|SPONSOR|REG|SITE|20260612160500||CSU^C09^CSU_C09|MSG00488|P|2.5.1
PID|1||PT-90031^^^SPONSOR^MR||Doe^Jane^A||19710204|F
CSR|STUDY2024-ONC-17^^^SPONSOR^STUDY|||PT-90031^^^SPONSOR^MR||20260601103000|||||||EVAL^Evaluable^L|20260612160000|COMPLETED^Protocol Completed^L
FHIR mapping
CSR is not mapped at the segment level. No segment-level ConceptMap is published in the v2-to-FHIR IG for CSR. Conceptually, CSR aligns with the FHIR ResearchSubject resource (the patient's participation in a study) and references a ResearchStudy (the protocol identified by CSR-1). When normalizing to FHIR, implementers typically derive ResearchSubject.status from CSR-10 and CSR-14, ResearchSubject.period.start from CSR-6, and the study reference from CSR-1. These are implementer conventions, not a published normalized mapping.
Engine considerations
- Most interface engines treat CSR as a Z-adjacent specialty segment; confirm the engine ships a CSU C09 structure or accept it as a generic segment.
- Repeating fields CSR-7, CSR-8, CSR-11, CSR-12, and CSR-13 must be configured to preserve repetitions; flattening them loses authorizing providers and stratification data.
- Validate that CSR-1 is non-empty before routing, since it is the protocol key.
- When converting CE coded fields to CWE for a 2.7+ partner, map component 1 (identifier), 2 (text), and 3 (coding system) carefully.
- Preserve timezone offsets in TS fields (CSR-6, CSR-9, CSR-11, CSR-15) so registration and randomization times remain unambiguous.
How Vorro parses and produces CSR
- On inbound CSU messages, Vorro reads CSR positionally per the HAPI v2.5.1 structure and normalizes each repeating field into a list, preserving order.
- CSR-1 Sponsor Study ID is required on parse; a missing value raises a validation event rather than silently dropping the segment.
- TS fields are normalized to a primary internal timestamp form with timezone retained, and re-rendered to HL7 TS on output.
- On production, Vorro emits CE coded fields by default and can transform them to CWE for partners on 2.7 or later via a configurable rule.
- Repeating provider and randomization fields are round-tripped without collapsing, so an inbound multi-arm or multi-provider CSR is reproduced faithfully.
Related pages
- /academy/hl7/segments/csp
- /academy/hl7/segments/css
- /academy/hl7/messages/csu
