HL7 CRM_C01 Clinical Trial Registration

A trial system tells the rest of the hospital that a patient has been registered on a study.
HL7 message structure CRM_C01 groups and segments from HL7 v2.5.1 Hide structure

These are the generated groups and segments for the version selected at the top of the page. The article explains the workflow, and this panel follows the chosen HL7 version.

Message Structure

SegmentNameRequiredRepeatable
MSH
 Message Header Yes No
SFT
 Software Segment No Yes
CRM_C01.PATIENT
 Patient group Yes Yes
PID
 Patient Identification Yes No
PV1
 Patient Visit No No
CSR
 Clinical Study Registration Yes No
CSP
 Clinical Study Phase No Yes

CRM_C01 is used when a patient is registered on a clinical trial. In practice, the sender is usually a clinical trials system, research module, oncology platform, or patient-data system. Receivers might include order entry, pharmacy, accounting, nursing, billing, or a sponsor-facing integration service.

The message is not just a demographic notification. The useful part is the study registration context: which protocol, which subject identifier, who authorized it, and which phase or arm applies now.

A small CRM C01 example

MSH|^~\&|TRIALS|CITYHOSP|PHARM|CITYHOSP|20260718120000||CRM^C01^CRM_C01|CRMC010001|P|2.5.1 PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L||19800314|F PV1|1|O|ONC^12^^CITYHOSP CSR|STUDY-2026-07^SPONSOR|ALT-77^CITYHOSP|CITYHOSP^City Hospital^L|SUBJ-10045^^^SPONSOR^AN||20260718113000|7788^Trial^Tara|9911^Oncologist^Owen|20260717100000|ELIG^Eligible^L CSP|ARM-A^Treatment arm A^L|20260718113000

What systems do with it

The receiver typically records that this patient is now known to a study. Pharmacy may use it to enable investigational-drug dispensing rules. Order entry may use it to show protocol order sets. Accounting may use the study identifiers to split research charges from standard care. Nursing systems may show protocol context next to the visit.

CRM_C01 is part of a clinical trial registration family. C01 registers the patient; nearby events use the same general shape to cancel, update, or change phase details. Interface engines often route all of these through the same map and branch on MSH-9.

How to read the structure

MSH identifies the event as CRM^C01^CRM_C01. PID identifies the patient, and optional PV1 gives visit context when the registration is tied to an encounter.

CSR is the heart of the message. It carries the sponsor study identifier, subject identifier, registration timestamp, and authorizing provider. Repeating CSP segments describe the phase, arm, cycle, or other local phase concept that downstream systems need.

Implementation traps

Do not treat the sponsor subject ID as a hospital MRN. Keep the study identifier, subject identifier, visit number, and local patient identifier in their own lanes. Confusing them is how trial patients end up with duplicate records or research orders attached to the wrong account.

Also agree what a phase code means. In one site it may be a protocol phase; in another it may be an arm, dose level, cycle, or visit milestone. The code system behind CSP matters more than the short label.

Reference notes

The HL7 v2 clinical study administration material describes CRM_C01 as the clinical study registration message and shows it being broadcast from a clinical trials or patient-data system to systems such as order entry, pharmacy, accounting, nursing, and external receivers. See the HL7 refactored CRM_C01 message page.