HL7 — Health Level Seven International

What Is HL7?

HL7 (Health Level Seven) is a set of international standards for the exchange, integration, sharing, and retrieval of electronic health information. Developed by Health Level Seven International—a not-for-profit standards organization—HL7 defines how clinical and administrative data should be packaged, transmitted, and interpreted between healthcare software systems.

The most widely deployed version is HL7 v2.x, a messaging standard that uses pipe-delimited segments (ADT, ORM, ORU, etc.) to communicate events such as patient admissions, lab orders, and results. Its successor, HL7 v3 / CDA, introduced XML-based document architectures. More recently, FHIR (Fast Healthcare Interoperability Resources) has emerged as the modern evolution of the HL7 family, leveraging RESTful APIs and JSON.

Why It Matters in Healthcare

In a typical hospital, dozens of systems need to talk to each other: the HIS sends orders to the LIS and RIS; the lab sends results back; the pharmacy validates prescriptions; the billing system captures charges. Without a common language, each pair of systems would require a custom, point-to-point interface—an approach that becomes unsustainable at scale.

HL7 provides that common language:

• Standardized messages: ADT (Admit/Discharge/Transfer), ORM (Order), ORU (Result), and SIU (Scheduling) messages cover the most common clinical workflows.
• Vendor neutrality: Any HL7-compliant system can exchange data with any other, regardless of vendor.
• Regulatory alignment: Many national and regional health IT mandates reference HL7 as the baseline for interoperability.
• Complementary to DICOM: While DICOM governs imaging data, HL7 handles the textual and demographic data that accompanies it, creating a complete information loop.

How Davix Relates to HL7

Every Davix product is built with interoperability at its core. The Davix HIS, LIS, and PACS/RIS all support HL7 v2.x messaging natively, enabling:

• Bidirectional order-result workflows between the HIS, LIS, and external laboratories.
• ADT event broadcasting so that every connected system reflects real-time patient movement.
• Result delivery to referring physicians and patient portals.
• Seamless coexistence with legacy systems that have not yet migrated to FHIR.

For organizations ready to adopt newer standards, Davix also provides FHIR APIs, allowing a gradual, risk-managed transition from HL7 v2 to modern RESTful hospital integration patterns.