Healthcare Data GlossaryTech
HL7: Definition and Healthcare Context
Full name: Health Level Seven International
Health Level Seven International (HL7) is an accredited standards development organization that creates frameworks and standards for health information technology. HL7 develops messaging standards (HL7 v2.x), clinical document standards (C-CDA / CDA), and the modern FHIR interoperability standard. The name 'Level Seven' refers to the seventh layer of the ISO OSI model — the application layer. HL7 v2 messages remain the most widely deployed health care data exchange format in hospital information systems globally.
Last updated: 2026-05-31Reviewed by: Dr. Jennifer Montecillo, MD — Gullas College of Medicine, 2019. Non-practicing medical reviewer.
How it’s used
- CMS NPPES NPI Registry: Fonteum's FHIR implementation is built on HL7 FHIR R4 US Core 6.1.0 profiles, exposing NPPES data as conformant HL7 resources.
Frequently asked questions
- What is HL7?
- HL7 (Health Level Seven International) is the standards body that develops data exchange standards for health care, including HL7 v2, C-CDA, and FHIR.
- What does 'Level Seven' mean in HL7?
- Level Seven refers to the top (application) layer of the ISO OSI model — HL7 standards define how applications communicate health information at that level.
- Is HL7 v2 still used?
- Yes. HL7 v2 messages are still the most common format for hospital-to-hospital data exchange, even as FHIR-based APIs expand.