Returns a query response containing the requested data. The QAK segment reports the query status, QPD echoes the original query parameters, and the payload segments carry the result data. Query-response workflows consume this.
# Zato
from zato.hl7v2 import HL7Message
# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
'RSP^K21^RSP_K21|MSG001|P|2.9\r' \
'QAK|QRY001|OK|Q22\r' \
'QPD|Q22^FindCandidates|QRY001|SMITH^JOHN'
# .. parsed into a Python object ..
msg = HL7Message.parse(raw)
# .. whose fields we can now access.
query_tag = msg.qak.query_tag
status = msg.qak.query_response_status
query_name = msg.qpd.message_query_name
query_tag = msg.qpd.query_tagHow to construct, send, receive, and extract fields from real-world RSP^K21 messages.
Demonstrates receiving and extracting key fields from a get person demographics response transaction
# Zato
from zato.hl7v2 import HL7Message
# An incoming message ..
raw = 'MSH|^~\&|SENDER|FAC|RCV|DEST|20260701||' \
'RSP^K21^RSP_K21|MSG001|P|2.9\r' \
'QAK|QRY001|OK|Q22\r' \
'QPD|Q22^FindCandidates|QRY001|SMITH^JOHN'
# .. parsed into a Python object ..
msg = HL7Message.parse(raw)
# .. whose fields we can now access.
query_tag = msg.qak.query_tag
status = msg.qak.query_response_status
query_name = msg.qpd.message_query_name
query_tag = msg.qpd.query_tagStep-by-step guides for working with HL7 v2 in Zato.
Use the HL7v2 message parser to extract the typed structure. The parsed message gives you direct access to every segment and field by name.
from zato.hl7v2 import HL7Message
raw = 'MSH|^~\&|SENDER|FACILITY|RECEIVER|DEST|20260401120000||RSP^K21^RSP_K21|MSG00001|P|2.9\rMSA|AA|MSG00001\rERR|||0|I|\rQAK|QRY-2001|OK\rQPD|QRY-1001|QRY-2001|\rDSC|CONT-001'
msg = HL7Message.parse(raw)
query_tag = msg.qak.query_tag
status = msg.qak.query_response_statusBeyond the mandatory MSH header, the required segments are: MSA, QAK, QPD, PID, QRI. Optional segments provide additional detail when available.
Zato connects to any system that speaks HL7v2 over MLLP or FHIR over REST. This includes Epic, Cerner, Meditech, Allscripts, and other EHR platforms.
Yes, Zato has built-in MLLP support for sending and receiving HL7v2 messages. MLLP channels handle the framing protocol automatically.
Zato supports HL7 v2.9, which is backward compatible with earlier versions including v2.3, v2.5, and v2.7. Standard segments and datatypes are available as typed Python classes.
Yes. Zato handles both HL7v2 and FHIR natively, so you can parse v2 messages and build FHIR resources with IG-specific extensions in the same service. Typed Python classes are available for both protocols, including extensions from US Core, UK Core, Da Vinci, and other Implementation Guides.
Segments that make up the RSP^K21 message, in order. Groups are shown with their child segments.
| # | Segment | Usage | Repeats | Description | Group |
|---|---|---|---|---|---|
| 1 | MSH | Required | No | Message header | - |
| 2 | ARV | Optional | Yes | Access restriction | - |
| 3 | SFT | Optional | Yes | Software segment | - |
| 4 | UAC | Optional | No | User authentication credential | - |
| 5 | MSA | Required | No | Message acknowledgment | - |
| 6 | ERR | Optional | No | Error | - |
| 7 | QAK | Required | No | Query acknowledgment | - |
| 8 | QPD | Required | No | Query parameter definition | - |
| 9 | PID | Required | No | Patient identification | QUERY_RESPONSE |
| 10 | PD1 | Optional | No | Patient additional demographic | QUERY_RESPONSE |
| 11 | ARV | Optional | Yes | Access restriction | QUERY_RESPONSE |
| 12 | NK1 | Optional | Yes | Next of kin / associated parties | QUERY_RESPONSE |
| 13 | QRI | Required | No | Query response instance | QUERY_RESPONSE |
| 14 | DSC | Optional | No | Continuation pointer | - |
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