HL7 (Health Level Seven)
HL7 is the older messaging standard for exchanging clinical data between healthcare systems, and it is still widely used alongside FHIR. Many hospital systems still run HL7 v2 interfaces for lab results and admissions, so a platform integrating with real providers usually needs to support both.
Key takeaways
- Long-standing messaging standard, still pervasive in hospitals
- Carries lab results, admissions, and orders via interface engines
- Loose enough that each site adds its own conventions
- Real integrations usually need both HL7 and FHIR
- Mapping and testing against actual feeds is essential
What HL7 means
HL7, and specifically HL7 v2, is the older messaging standard that has quietly carried clinical data between hospital systems for decades. It uses a compact, pipe-and-hat text format that is far from modern but deeply embedded in how labs, admissions, and orders move around a hospital. Despite the arrival of FHIR, it remains everywhere, because replacing working interfaces in a live clinical environment is slow and risky.
In practice, HL7 v2 messages flow through an interface engine that routes and transforms them between systems, and each hospital tends to have its own local conventions layered on top. The standard is flexible to the point of being loose, so two sites can send the same message type with meaningfully different content. That variability is why real-world HL7 work leans heavily on careful mapping and testing against each provider's actual feeds.
For a buyer, the takeaway is that supporting real providers usually means supporting both HL7 and FHIR, not choosing one. A modern platform might expose FHIR outward while still consuming HL7 v2 feeds from the hospital. Any partner you work with should be comfortable in that messy middle, where old and new standards coexist.