HL7 OBR Segment: Observation Request

The HL7 OBR segment (Observation Request) defines what was ordered and its current status. It appears in ORM (order) and ORU (result) messages, linking the order details to individual results carried in OBX segments. The OBR acts as the “header” for a group of related observations.

OBR Field Reference

Seq	Name	Type	Opt	Description
`OBR-1`	Set ID	SI	O	Sequence number for multiple OBRs
`★ OBR-2`	Placer Order Number	EI	R	Order ID from ordering system
Assigned by the ordering system (CPOE). Must be echoed in all subsequent messages for this order so results can be matched back.
`★ OBR-3`	Filler Order Number	EI	R	Order ID from fulfilling system
Accession number assigned by the fulfilling system (lab/radiology). Must be preserved through the entire order-result lifecycle.
`★ OBR-4`	Universal Service Identifier	CE	R	LOINC code or local test code
Best practice: use LOINC codes (e.g., 24323-8^CMP^LN). Integration engines map between local codes and standard codes during transformation.
`OBR-5`	Priority	ID	O	Routine, STAT, ASAP
`OBR-6`	Requested Date/Time	TS	O	When the test was requested
`★ OBR-7`	Observation Date/Time	TS	O	Specimen collection time
When the specimen was actually collected. Critical for clinical decisions on time-sensitive tests (blood cultures, lactate, troponin).
`OBR-8`	Observation End Date/Time	TS	O	End of observation period
`OBR-9`	Collection Volume	CQ	O	Specimen volume
`OBR-10`	Collector Identifier	XCN	O	Person who collected specimen
`OBR-11`	Specimen Action Code	ID	O	A (Add), G (Generate), L (Lab)
`OBR-12`	Danger Code	CE	O	Patient danger codes
`OBR-13`	Clinical Information	ST	O	Relevant clinical history
`OBR-14`	Specimen Received Date/Time	TS	O	When lab received the specimen
`OBR-15`	Specimen Source	SPS	O	Specimen type and body site
`★ OBR-16`	Ordering Provider	XCN	O	Provider who placed the order
Also carried in ORC-12. When both are present, ORC-12 takes precedence per the HL7 standard.
`OBR-17`	Order Callback Phone	XTN	O	Phone for critical results
`OBR-18`	Placer Field 1	ST	O	User-defined placer data
`OBR-19`	Placer Field 2	ST	O	User-defined placer data
`OBR-20`	Filler Field 1	ST	O	User-defined filler data
`OBR-21`	Filler Field 2	ST	O	User-defined filler data
`★ OBR-22`	Results Report Date/Time	TS	O	When results were reported
When results were finalized and available. Turnaround time (TAT) = OBR-22 minus OBR-7 (collection time) — a key lab quality metric.
`OBR-23`	Charge to Practice	MOC	O	Charge code
`★ OBR-24`	Diagnostic Service Section	ID	O	LAB, RAD, PATH, etc.
Department codes: LAB, CH (Chemistry), HM (Hematology), MB (Microbiology), RAD (Radiology), PATH (Pathology), BLB (Blood Bank), etc.
`★ OBR-25`	Result Status	ID	O	O, I, S, A, P, C, R, F, X, Y
Order-level status: F=Final, P=Preliminary, C=Correction, X=Cancelled. Distinct from OBX-11 which is the individual result status.
`OBR-26`	Parent Result	PRL	O	Links to parent order
`OBR-27`	Quantity/Timing	TQ	O	Collection schedule (deprecated in v2.5+)
`OBR-28`	Result Copies To	XCN	O	Providers to receive result copies
`OBR-29`	Parent Number	EIP	O	Parent order identifier
Links child orders to parent. Used in reflex testing, add-on tests, and culture with sensitivities.
`OBR-30`	Transportation Mode	ID	O	Transport method for specimen
`OBR-31`	Reason for Study	CE	O	Diagnosis/reason for the test
`OBR-32`	Principal Interpreter	NDL	O	Pathologist/radiologist
`OBR-33`	Assistant Interpreter	NDL	O	Assistant interpreter
`OBR-34`	Technician	NDL	O	Lab technician
`OBR-44`	Procedure Code	CE	O	CPT procedure code
`OBR-45`	Procedure Code Modifier	CE	O	CPT modifiers

OBR-1 O

Set ID SI

Sequence number for multiple OBRs

★ OBR-2 R

Placer Order Number EI

Order ID from ordering system

Assigned by the ordering system (CPOE). Must be echoed in all subsequent messages for this order so results can be matched back.

★ OBR-3 R

Filler Order Number EI

Order ID from fulfilling system

Accession number assigned by the fulfilling system (lab/radiology). Must be preserved through the entire order-result lifecycle.

★ OBR-4 R

Universal Service Identifier CE

LOINC code or local test code

Best practice: use LOINC codes (e.g., 24323-8^CMP^LN). Integration engines map between local codes and standard codes during transformation.

OBR-5 O

Priority ID

Routine, STAT, ASAP

OBR-6 O

Requested Date/Time TS

When the test was requested

★ OBR-7 O

Observation Date/Time TS

Specimen collection time

When the specimen was actually collected. Critical for clinical decisions on time-sensitive tests (blood cultures, lactate, troponin).

OBR-8 O

Observation End Date/Time TS

End of observation period

OBR-9 O

Collection Volume CQ

Specimen volume

OBR-10 O

Collector Identifier XCN

Person who collected specimen

OBR-11 O

Specimen Action Code ID

A (Add), G (Generate), L (Lab)

OBR-12 O

Danger Code CE

Patient danger codes

OBR-13 O

Clinical Information ST

Relevant clinical history

OBR-14 O

Specimen Received Date/Time TS

When lab received the specimen

OBR-15 O

Specimen Source SPS

Specimen type and body site

★ OBR-16 O

Ordering Provider XCN

Provider who placed the order

Also carried in ORC-12. When both are present, ORC-12 takes precedence per the HL7 standard.

OBR-17 O

Order Callback Phone XTN

Phone for critical results

OBR-18 O

Placer Field 1 ST

User-defined placer data

OBR-19 O

Placer Field 2 ST

User-defined placer data

OBR-20 O

Filler Field 1 ST

User-defined filler data

OBR-21 O

Filler Field 2 ST

User-defined filler data

★ OBR-22 O

Results Report Date/Time TS

When results were reported

When results were finalized and available. Turnaround time (TAT) = OBR-22 minus OBR-7 (collection time) — a key lab quality metric.

OBR-23 O

Charge to Practice MOC

Charge code

★ OBR-24 O

Diagnostic Service Section ID

LAB, RAD, PATH, etc.

Department codes: LAB, CH (Chemistry), HM (Hematology), MB (Microbiology), RAD (Radiology), PATH (Pathology), BLB (Blood Bank), etc.

★ OBR-25 O

Result Status ID

O, I, S, A, P, C, R, F, X, Y

Order-level status: F=Final, P=Preliminary, C=Correction, X=Cancelled. Distinct from OBX-11 which is the individual result status.

OBR-26 O

Parent Result PRL

Links to parent order

OBR-27 O

Quantity/Timing TQ

Collection schedule (deprecated in v2.5+)

OBR-28 O

Result Copies To XCN

Providers to receive result copies

OBR-29 O

Parent Number EIP

Parent order identifier

Links child orders to parent. Used in reflex testing, add-on tests, and culture with sensitivities.

OBR-30 O

Transportation Mode ID

Transport method for specimen

OBR-31 O

Reason for Study CE

Diagnosis/reason for the test

OBR-32 O

Principal Interpreter NDL

Pathologist/radiologist

OBR-33 O

Assistant Interpreter NDL

Assistant interpreter

OBR-34 O

Technician NDL

Lab technician

OBR-44 O

Procedure Code CE

CPT procedure code

OBR-45 O

Procedure Code Modifier CE

CPT modifiers

R = Required, O = Optional, C = Conditional, W = Withdrawn (backward compatibility only)

OBR-4: Universal Service Identifier

OBR-4 identifies the ordered test or procedure. Best practice is to use LOINC codes:

OBR|1|ORD5678^EPIC|FIL9012^LAB_SYS|24323-8^CMP^LN||...

Component	Value	Meaning
CE.1	24323-8	LOINC code
CE.2	CMP	Display name (Comprehensive Metabolic Panel)
CE.3	LN	LOINC coding system

Many lab systems use local codes in addition to or instead of LOINC. The integration engine typically maps between local codes and standard codes during transformation.

OBR-25: Result Status Codes

Status	Meaning	Description
O	Order received	Specimen not yet received
I	Specimen in lab	Received, not started
S	Scheduled	Specimen scheduled for testing
A	Partial results	Some results available
P	Preliminary	Results not yet verified
C	Correction	Corrected final result
R	Entered (Not Verified)	Results entered, pending verification
F	Final	Verified, complete result
X	Cancelled	Order/test cancelled
Y	No order on file	Results for unknown order

OBR-24: Diagnostic Service Sections

Code	Department
LAB	Laboratory (general)
CH	Chemistry
HM	Hematology
MB	Microbiology
SR	Serology
RAD	Radiology
NRS	Nursing
PATH	Pathology
PHR	Pharmacy
BLB	Blood Bank
CTH	Cardiac Catheterization
NMS	Nuclear Medicine
OUS	Ultrasound
SP	Surgical Pathology
CYT	Cytology

Key Implementation Considerations

Placer vs Filler Numbers

OBR-2 (Placer): Assigned by the ordering system. This is the order number the provider sees in the CPOE.
OBR-3 (Filler): Assigned by the fulfilling system. This is the accession number in the lab/radiology system.

Both must be preserved through the order-result lifecycle. When the lab returns results (ORU), it echoes back the placer number in OBR-2 so the ordering system can match results to the original order.

Specimen Collection Time (OBR-7)

OBR-7 is crucial for lab results — it records when the specimen was actually collected, not when the order was placed or the result was reported. Clinical decision-making depends on knowing the collection time, especially for time-sensitive tests like blood cultures, lactate, and troponin.

Result Report Time (OBR-22)

OBR-22 records when the results were reported (finalized and available). The time difference between OBR-7 (collection) and OBR-22 (reported) is the turnaround time (TAT), a key lab quality metric.

Parent-Child Orders

OBR-29 (Parent Number) links child orders to a parent. Common scenarios:

Reflex testing: An abnormal result triggers a follow-up test (e.g., abnormal TSH reflexes to Free T4)
Add-on tests: Additional tests added to an existing specimen
Culture with sensitivities: The sensitivity panel is a child of the original culture order

HL7 ORM Messages ORM message structure — the primary carrier of OBR segments for clinical orders.

HL7 ORU Messages ORU message structure — OBR segments paired with OBX results.

HL7 Resource Center Message types, segments, reference guides, and integration tools.