HL7 Integration - NHS Carenostix

What is HL7?

HL7 (Health Level 7) is the international standard for healthcare data exchange. Carenostix implements HL7 v2.5 for:

Order transmission (ORM^O01 messages)
Result reporting (ORU^R01 messages)
System acknowledgments (ACK messages)
Clinical order routing to LIMS systems

Supported Message Types

Message Type	Purpose	Direction
ORM^O01	Order message - send tests to lab	Outbound (GP → Lab)
ORU^R01	Result message - receive lab results	Inbound (Lab → GP)
ACK^O01	Acknowledgment - order accepted/rejected	Bidirectional
ADT^A01	Patient admission/update	Inbound

Message Segments

Standard HL7 segments used in Carenostix:

MSH: Message header with control IDs and timestamp
EVN: Event type (order created, result received, etc)
PID: Patient identification and demographics
PV1: Patient visit information
ORC: Order control segment
OBR: Observation request (test order)
OBX: Observation/result segment
NTE: Notes and comments

Example HL7 Messages

Sending an Order (ORM^O01)

MSH|^~\&|CARENOSTIX|NHS001|LIMS|LAB001|20250101120000||ORM^O01|MSG001|P|2.5
EVN|O01|20250101120000
PID|||1234567890||DOE^JOHN||19800101|M
ORC|NW|CNX20250101120000ABC|||||||||GP001^SMITH
OBR|1|CNX20250101120000ABC||00000000^FBC|||20250101
OBX|1|NM|00000000^RBC||4.5|10\12/L|4.0-6.0|N|||F
            

Integration Setup

Step 1: Configure LIMS endpoint URL and credentials

Step 2: Set HL7 sending facility and application IDs

Step 3: Map local test codes to SNOMED-CT codes

Step 4: Enable message validation and audit logging

Step 5: Test message transmission with LIMS system

Step 6: Deploy to production with monitoring

API Endpoints for HL7

POST /api/hl7/send
- Send HL7 orders to LIMS systems

POST /api/hl7/receive
- Receive HL7 results from LIMS systems

GET /api/hl7/messages/{messageId}
- Retrieve HL7 message history

POST /api/hl7/validate
- Validate HL7 message syntax
            