Towards Seamless Data Integration: A Comparative Study of HL7, FHIR, and LOINC in SaaS Laboratory Systems

In the evolving landscape of healthcare technology, seamless data integration is critical for efficient laboratory information exchange. This study explores and compares three major interoperability standards—Health Level Seven (HL7), Fast Healthcare Interoperability Resources (FHIR), and Logical Observation Identifiers Names and Codes (LOINC)—in the context of Software-as-a-Service (SaaS) laboratory systems. The purpose of the study is to evaluate how each standard facilitates data sharing, system interoperability, and clinical decision-making within cloud-based laboratory infrastructures. A mixed-methods approach was employed, combining technical feature analysis, performance benchmarking, and qualitative interviews with health IT professionals. HL7 was evaluated for its legacy integration capacity, FHIR for its modern API-based architecture, and LOINC for its semantic consistency in lab results encoding. Key findings reveal that FHIR offers superior flexibility and developer-friendly integration via RESTful APIs, making it ideal for modern SaaS architectures. HL7, while widely adopted, presents challenges in adaptation due to its rigidity and reliance on older messaging formats. LOINC, when used in conjunction with either HL7 or FHIR, significantly enhances semantic interoperability by standardizing lab test identifiers. The study concludes that a hybrid approach, leveraging FHIR for data exchange and LOINC for terminology management, presents the most effective strategy for achieving seamless integration in SaaS laboratory systems.