HL7 Version 2 (HL7 v2)

Why it matters

Laboratory analysers, radiology information systems and most hospital interfaces already speak HL7 v2, so any system a hospital buys must exchange it competently. A systematic review of 80 FHIR implementation studies concluded that FHIR might take years or decades to replace legacy standards [3]. In practice, hospitals run both.

Key points

• HL7 Version 2 was first published in October 1987 [1].
• HL7 reports that more than 95 percent of healthcare organisations in the United States use it, and that implementations exist in more than 35 countries [1].
• The standard is organised by domain, including patient administration, orders, observations, scheduling, financial management and clinical laboratory automation [1].
• Messages are triggered by events: a patient is admitted, an order is placed, a result is verified, and the receiving system acts on it.
• Interfaces are point to point and local variation is common, so each one needs mapping and testing. FHIR is the complement for exchange between organisations and applications [2].

In Moana

Moana exchanges HL7 v2 messages with hospital systems, and MOANA LIS integrates with analysers and instruments, so results arrive in the record without transcription.

Sources

1. HL7 Version 2 product description, HL7 International, accessed 2026
2. FHIR R4 overview for developers, HL7 International, 2019
3. The FHIR standard: systematic literature review of implementations, applications, challenges and opportunities, JMIR Medical Informatics, 2021