Send HL7 Message

Credential	Type	Required	Description
Network Access	IP	Yes	Authorised network access.

Credential

Type

Required

Description

Network Access

Yes

Authorised network access.

Message format

The message must be framed using the MLLP protocol. The receiver also accepts messages with missing start or end blocks.

Component	Required	Description
Start Block	No	MLLP start-of-message marker. Recommended for standard compliance.
HL7 Content	Yes	A valid HL7 v2.4 message with pipe-delimited segments.
End Block	No	MLLP end-of-message marker. Recommended for standard compliance.

Message segments

The receiver processes the following HL7 segments from each inbound message.

Segment	Description
Message Header	Identifies sending and receiving applications, message type, and version.
Event	Describes the event (e.g. admission, discharge).
Patient Identity	Patient demographics: name, DOB, gender, address.
Patient Visit	Visit details: location, attending doctor, admission/discharge times.
Visit Additional	Supplementary visit information (e.g. expected discharge date).
Next of Kin	Emergency contacts and relationship to patient.
Insurance	Insurance plan and policy information.

Response

The receiver returns an HL7 acknowledgment (ACK) over the same TCP connection. The ACK always indicates acceptance to avoid retry loops from the sending system.

MSH|...|ACK|{Control ID}|P|2.4
MSA|AA|{Control ID}

The receiver always returns an accept acknowledgment. Processing failures are tracked internally and do not produce a negative ACK to the sender.

Error handling

Condition	Acknowledgment Sent	Internal Status
Message processed successfully	Accept	Processed
Invalid or missing clinic service	Accept	Clinic Rejected
Invalid patient identifier format	Accept	Partial
Malformed or unparseable message	Accept	Failed
Message decode failure	Accept	Failed
Empty or zero-length message	Accept	Health Check

For authentication credentials and access setup, contact the medWrite team.

Authentication

Get Records

HL7 Receiver

Connection

Authentication

Message format

Message segments

Response

Error handling

Next steps

HL7 Phases

Get Approved Outputs

​Connection

​Authentication

​Message format

​Message segments

​Response

​Error handling

​Next steps

HL7 Phases

Get Approved Outputs

Connection

Authentication

Message format

Message segments

Response

Error handling

Next steps