Healthcare interoperability standards explained
HL7 version 2 remains the workhorse inside hospitals, carrying event messages such as patient admissions and transfers, lab orders and results. FHIR, the newer HL7 standard, models data as resources such as Patient, Observation and MedicationRequest, exposed through RESTful APIs, and it underpins modern health data exchange, including India's ABDM, whose FHIR profiles are published by the national resource center for EHR standards. DICOM governs medical imaging and its exchange. Most hospitals run several of these standards at once.
Terminologies give data shared meaning: SNOMED CT for clinical terms, LOINC for lab tests and ICD-10 for diagnoses and billing. In the US, ONC certification rules and information blocking provisions push providers toward FHIR APIs, and SMART on FHIR lets apps launch securely inside EHRs.
- HL7 v2: event messages between hospital systems.
- FHIR: resource-based APIs for modern data exchange.
- DICOM: imaging data and communication.
- SNOMED CT, LOINC and ICD-10: shared clinical codes.
- SMART on FHIR: secure app launch and authorization inside EHRs.
- IHE profiles: tested patterns for common integration scenarios.



