What is HL7 (Health Level Seven)?

HL7 (Health Level Seven) Definition

HL7 is the "Grammar and Syntax" of healthcare data. Founded in 1987, it created the language that allowed different hospital systems (like the Pharmacy and the Lab) to talk to each other for the first time. For Payer Ops, HL7 v2 "ADT" (Admission, Discharge, Transfer) messages are critical for tracking when a member enters a hospital. For C-Suite leaders, HL7 represents the legacy foundation of their IT stack. While version 2 is the most widely used globally, version 3 and the Clinical Document Architecture (CDA) introduced more complex, XML-based data structures. Strategically, HL7 International is the parent organization that also developed FHIR, ensuring a bridge between old-school messaging and new-school APIs.

FAQs

What does the "7" in HL7 stand for?

It refers to the 7th layer (the Application Layer) of the ISO Open Systems Interconnection (OSI) model for communications.

What is an "ADT Message"?

The most common HL7 v2 message type; it signals that a patient has been Admitted, Discharged, or Transferred within a healthcare facility.

Why is HL7 v3 considered difficult?

It was mathematically precise but overly complex to implement, leading the industry to move toward FHIR for modern integration needs.