Interoperability and Health Information Exchange Standards
Core concepts
Know the standards landscape: HL7 v2 (messaging), HL7 v3/CDA (documents), FHIR (RESTful resources), and the role of IHE profiles. Understand transport: MLLP, SOAP, REST, and secure transport (TLS). Know terminology standards (SNOMED CT, LOINC, RxNorm, ICD-10, CPT) and the value sets that bind them. Understand HIE models: centralized, federated, and hybrid, plus query-based vs. push-based exchange. Learn consent models (opt-in, opt-out, no-consent) and their effect on data availability. Know the role of USCDI, the ONC certification criteria, and TEFCA at a conceptual level.
Traps
Questions confuse CDA (document-centric) with FHIR (resource-centric). Another trap: assuming an interface engine fixes semantic mismatch - it fixes syntax, not meaning. Also watch for conflating consent model with authorization to treat.
Rule of thumb
Interoperability has three layers: transport, syntax, and semantics. Most failures are semantic - the same concept coded differently.
Worked example
Two systems exchange a lab result. Transport succeeds, HL7 v2 parses, but the result is unusable because the unit is missing. The fix is a value set and unit mapping, not a new interface.