Glossary
HL7 (Health Level Seven)
The standards organization behind the HL7 v2 messages, CDA documents and FHIR APIs that most EHRs use to exchange data with other systems.
What does HL7 (Health Level Seven) mean in clinical research?
Health Level Seven International (HL7), founded in 1987, is a not-for-profit, ANSI-accredited standards developing organization dedicated to the interoperability of healthcare data. Its standards include FHIR, Version 2 (V2) and CDA, and the name refers to the application layer, the seventh layer of the ISO networking model. HL7 reports community members from more than 50 countries, including more than 500 corporate members.[1]
In hospital IT, "HL7" often means HL7 v2 messages: the event feeds for admissions, orders and lab results that systems inside a health system send one another. FHIR is HL7's newer, API-based standard, and certified EHRs must offer a FHIR Release 4.0.1 API.[2] For recruitment, either can carry the data a screening tool needs, and many health systems run both.
Practical note: ask the site's integration team which interfaces already exist before scoping a new one. Reusing an existing HL7 v2 feed or FHIR endpoint can shorten IT review. Bond connects via FHIR R4 APIs, HL7 v2 where applicable, or an integration partner; see Implementation.
Sources
- 1.About HL7 · HL7 International, 2026
- 2.45 CFR 170.215 Application programming interfaces (API) standards and implementation specifications · eCFR (HHS ONC / ASTP), 2026