Send an HL7v2 ORU^R01 lab result message over MLLP

In-depth guide

Steps

1. Construct the HL7v2 ORU^R01 message with required segments: MSH (message header), PID (patient identification), OBR (observation request), and one or more OBX (observation result) segments encoding each lab value with LOINC codes in OBX-3 and result values with UCUM units in OBX-6
2. Wrap the message in MLLP framing: prepend the vertical-tab byte (0x0B) and append the field-separator byte (0x1C) followed by a carriage return (0x0D)
3. Open a TCP socket connection to the receiving system on its configured MLLP port (commonly 2575 or a site-specific port) and send the framed message bytes
4. Read the response bytes from the socket, strip the MLLP envelope, and parse the returned ACK message to check MSA-1 for AA (application accept), AE (application error), or AR (application reject)
5. On AE or AR, log the MSA-3 error text and the ERR segment details, then implement retry logic with back-off appropriate to your operational SLA
6. Close the TCP socket; for high-volume interfaces consider connection pooling rather than opening a new socket per message