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Interoperability

FHIR R4 in Ambulatory Care

Where FHIR-based interoperability stands in outpatient settings, and what it means for practices.

December 2025 11 min read White Paper

Authors

  • NexiumCare TeamEditorial

Key Findings

  • FHIR R4 has become the de facto interoperability standard for U.S. ambulatory care.
  • Standard adoption and standard parity are not the same thing.
  • Write parity and bulk export are where vendors still differ most.

Where FHIR Stands Today

Federal information-blocking rules and the 21st Century Cures Act have made FHIR R4 the de facto interoperability standard for U.S. ambulatory care. But standard adoption and standard parity are not the same thing — read access is widespread, while bidirectional write support remains uneven.

What FHIR Enables

On FHIR-native platforms, practices can plug into a growing ecosystem of clinical decision support, patient-facing apps, and analytics without custom integration work. The highest-value use cases tend to be:

  • Bidirectional referral exchange with hospital networks
  • Patient-mediated data sharing through SMART-on-FHIR apps
  • Embedded clinical decision support inside the chart
  • Population health analytics across multiple sites

What Comes Next

Expect bulk FHIR APIs and newer USCDI datasets to reshape what practices can offer. Vendors that lead on write parity and bulk export will become the default infrastructure layer for value-based care. (NexiumCare's own API and FHIR surface is on our roadmap.)

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