HL7 RSP_Z90 (Lab Results History Response) | Integration Soup HL7 Reference Guide

HL7 RSP_Z90 Lab Results History Response

A query response that returns prior lab results in patient, order, observation, and specimen groups.

HL7 message structure RSP_Z90 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

Segment	Name	Required	Repeatable
MSH	Message Header	Yes	No
SFT	Software Segment	No	Yes
MSA	Message Acknowledgment	Yes	No
ERR	Error	No	No
QAK	Query Acknowledgment	Yes	No
QPD	Query Parameter Definition	Yes	No
RCP	Response Control Parameter	Yes	No
RSP_Z90.QUERY_RESPONSE	Query Response group	Yes	Yes
RSP_Z90.PATIENT	Patient group	No	No
PID	Patient Identification	Yes	No
PD1	Patient Additional Demographic	No	No
NK1	Next of Kin / Associated Parties	No	Yes
NTE	Notes and Comments	No	Yes
RSP_Z90.VISIT	Visit group	No	No
PV1	Patient Visit	Yes	No
PV2	Patient Visit - Additional Information	No	No
RSP_Z90.COMMON_ORDER	Common Order group	Yes	Yes
ORC	Common Order	Yes	No
RSP_Z90.TIMING	Timing group	No	Yes
TQ1	Timing/Quantity	Yes	No
TQ2	Timing/Quantity Relationship	No	Yes
OBR	Observation Request	Yes	No
NTE	Notes and Comments	No	Yes
CTD	Contact Data	No	No
RSP_Z90.OBSERVATION	Observation group	Yes	Yes
OBX	Observation/Result	No	No
NTE	Notes and Comments	No	Yes
RSP_Z90.SPECIMEN	Specimen group	No	Yes
SPM	Specimen	Yes	No
OBX	Observation/Result	No	Yes
DSC	Continuation Pointer	Yes	No

RSP_Z90 returns lab results history. Unlike ORU_R01, which pushes a result when it is available, RSP_Z90 answers a query for prior results. The receiver uses it to fill a history screen, support clinical review, or reconcile old results into a repository.

The shape is familiar to anyone who has worked with lab messages: patient context, order/report headers, observation values, and specimen detail. The difference is the query envelope: MSA, QAK, QPD, and RCP tell you what was asked and what the server returned.

A small RSP Z90 example

MSH|^~\&|LAB|CITYLAB|PORTAL|CITYHOSP|20260718110000||RSP^Z90^RSP_Z90|RSPZ900001|P|2.5.1 MSA|AA|QBPZ890001 QAK|QLAB001|OK|Z89^Lab Results History^HL7nnn|1|1|0 QPD|Z89^Lab Results History^HL7nnn|QLAB001|123456^^^CITYHOSP^MR|20260701000000|20260717235959 RCP|I|20^RD PID|1||123456^^^CITYHOSP^MR||Smith^Jane^Anne^^Ms^^L||19800314|F PV1|1|O|CLINIC^12^^CITYHOSP ORC|RE|ORD448811^EHR|LAB998877^CITYLAB OBR|1|ORD448811^EHR|LAB998877^CITYLAB|718-7^Hemoglobin^LN|||20260715113000|||||||||12345^Careful^Clara||||||20260715142500|||F OBX|1|NM|718-7^Hemoglobin^LN||128|g/L|115-155|N|||F|||20260715142000 SPM|1|S25-0001&CITYLAB||BLD^Blood^HL70487 DSC|CONT-Z90-001|I

What systems do with it

The requester is usually a clinical viewer, portal, repository, or integration engine that needs prior lab data for a patient and date range. The sender is the lab, repository, or results server that can search historical results.

Use QAK to understand the query outcome before filing any result data. A message can be accepted and still return no rows, a partial result, or a continuation pointer.

How to read the structure

The required query-response group can repeat. It may include patient and visit context, one or more common-order groups with ORC, required OBR, repeating OBX observations, and optional CTD contact data. A specimen group can repeat with SPM and specimen-level OBX segments.

The local imported structure marks DSC as required. That means any implementation profile should be very clear about whether every response carries a pointer, whether the pointer can indicate the final page, and how the requester asks for the next increment.

Implementation traps

Do not merge historical results as if they were fresh ORU messages. Result status, correction status, timestamps, and order identifiers decide whether the receiver should display, replace, or ignore a result.

Also keep specimen context attached. When the same test code appears on multiple specimens, losing SPM can make a clean-looking history clinically misleading.

Reference notes

HL7 identifies event Z90 as Lab Results History (Response). The local RSP_Z90 structure uses query status plus patient, order, observation, and specimen groups. See HL7 Europe event Z90.