FHIR, pronounced "fire," stands for Fast Healthcare Interoperability Resources. It is a healthcare data exchange standard developed by HL7 International that defines how clinical and administrative data can be shared between different healthcare systems. Unlike its predecessors, FHIR was designed from the ground up to leverage modern web technologies, using RESTful APIs, JSON, and XML to make healthcare data exchange more accessible to developers and more efficient for organizations.
At the heart of FHIR is the concept of resources — modular, reusable data components that represent clinical concepts. A Patient resource contains demographic information, an Observation resource holds a single lab result, and a DiagnosticReport resource groups multiple observations together. These resources can be combined, referenced, and transmitted independently, providing remarkable flexibility in how healthcare data is structured and shared.
FHIR has rapidly become the dominant interoperability standard worldwide. It is mandated by regulations such as the US 21st Century Cures Act and is increasingly adopted across Europe, Latin America, and Asia. For laboratory data specifically, FHIR provides a clear structure for representing lab reports: a DiagnosticReport resource contains references to individual Observation resources, each coded with LOINC codes and carrying values with UCUM units.
In the context of lab report digitization, FHIR serves as the output format that transforms unstructured paper reports into structured, machine-readable data. Once OCR extracts text from a lab report and NLP maps test names to LOINC codes, the results are packaged into FHIR-compliant JSON that any standards-based healthcare system can consume. This pipeline bridges the gap between legacy paper-based workflows and modern digital health infrastructure.