HL7
Health Level Seven — legacy healthcare messaging standard (v2.x) for clinical and administrative data interchange. The dominant interface backbone in U.S. hospitals as of 2025, despite FHIR (HL7's modern RESTful successor) gaining ground in patient-facing and registry applications. Maintained by the HL7 organization.
Core message types in radiology integration:
- ADT — admit / discharge / transfer; patient demographics.
- ORM — order messages; new orders, cancellations.
- ORU — results; reports back to ordering systems.
- MDM — document management; reports, attachments.
- SIU — scheduling.
Why it matters to buyers: Underpins most hospital interfaces in clinical operation. RIS / PACS / EHR / modality-information-system traffic flows over HL7 v2. FHIR is the strategic successor but v2 is entrenched and won't disappear quickly. RFP language about "hospital integration" usually means HL7 v2 in practice.
Why it matters to engineers: Parsing is character-delimited (pipe / caret / tilde / ampersand / backslash hierarchy), not XML or JSON. Hospital interface engines (Mirth Connect, Cloverleaf, Rhapsody, Iguana, Corepoint) translate between HL7 dialects — v2 is famously variable across implementations, and "compatible" usually means "after the interface engine massages the message."