HL7 RDY_K15 Display Response

The display-line answer to a QBP_Q15 query.
HL7 message structure RDY_K15 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
MSA
 Message Acknowledgment Yes No
ERR
 Error No No
QAK
 Query Acknowledgment Yes No
QPD
 Query Parameter Definition Yes No
DSP
 Display Data No Yes
DSC
 Continuation Pointer No No

RDY_K15 is the display response for QBP_Q15. It reports whether the query worked, echoes the query definition, and returns optional DSP lines for the requester to show or interpret.

It sits between old DSR display responses and more structured QBP responses. You get QPD and QAK correlation, but the business payload is still display text.

A small RDY K15 example

MSH|^~\&|SUMMARY|CITYHOSP|PORTAL|CITYHOSP|20260717111502||RDY^K15^RDY_K15|RDY150001|P|2.5.1 MSA|AA|QBP150001 QAK|Q150001|OK|Q15^Medication summary display^HL7nnn|3 QPD|Q15^Medication summary display^HL7nnn|Q150001|123456^^^CITYHOSP^MR DSP|1||Active medication summary for Smith, Jane Anne DSP|2||Amoxicillin 500 mg capsule - one capsule three times daily DSP|3||Last updated 2026-07-15 10:30

What systems do with it

The requester reads MSA for transport/application acknowledgment, QAK for query status, and QPD for the echoed query name and tag. Then it displays or lightly parses the DSP lines.

If the response is longer than the requester asked for, DSC can continue it. The requester should either request the next increment or cancel the query when it has enough.

How to read the structure

MSH, MSA, optional ERR, QAK, and QPD establish what happened and what query was answered. Repeating DSP carries the display content. DSC is optional continuation.

DSP-3 is the line that users usually see. DSP-1 and DSP-2 can help order or group lines, but many implementations leave them simple. If the requester depends on those fields, document the convention.

Implementation traps

The trap is treating display text as stable data without a contract. If a receiving application is going to parse "Last updated" or "Active medication," that text has become an interface field and should be documented like one.

Also watch for partial responses. QAK hit counts and DSC continuation pointers tell the requester whether the visible lines are the whole answer or just the first slice.

Reference notes

The HL7 v2+ refactored RDY_K15 material shows a response with MSA, ERR, QAK, QPD, DSP, and DSC. The same page notes that QBP_Q15 and RDY_K15 may use standard or site-defined query profile trigger events.