Laboratory and diagnostic results flow from lab systems through FHIR into clinical charts. Understanding the flow prevents result-reporting bugs.
Flow overview
1. Order placed in EHR → ServiceRequest resource created. 2. Order sent to lab (typically HL7v2 ORM). 3. Lab performs test, reports results (HL7v2 ORU). 4. Results converted to FHIR (via HL7v2-to-FHIR converter). 5. Results land as Observation + DiagnosticReport resources. 6. Clinician reviews results in chart.
FHIR resources involved
1. ServiceRequest — the order. 2. Observation — individual results (glucose, WBC, etc.). 3. DiagnosticReport — aggregated result (CBC panel, culture report). 4. Specimen — specimen collected for testing. 5. PractitionerRole — ordering and interpreting practitioners.
LOINC codes for results
Lab tests use LOINC codes for Observation.code. Panels use LOINC panel codes; individual components use LOINC component codes. basedOn links Observation to the parent DiagnosticReport.
Reference ranges
Observation.referenceRange provides age/sex/context-specific normal ranges. Multiple ranges for different subpopulations.
Result interpretation flags
Observation.interpretation codes: H (high), L (low), A (abnormal), N (normal). Drives clinician alerts.
Common results integration mistakes
1. Missing basedOn link. Individual Observations orphaned from DiagnosticReport. 2. Wrong LOINC. Panel code where component was needed (or vice versa). 3. Missing reference ranges. Clinicians can't interpret without. 4. No interpretation. Alerts silent when they should fire. 5. Time coherence. effectiveDateTime should match specimen collection.
Regulatory context
CLIA requirements for lab result reporting; FDA for interpretive results; HIPAA for transmission security.
Vendor tooling
1. Lab-side: Epic Beaker, Cerner Millennium PowerChart lab modules. 2. Integration engines: Rhapsody, Mirth Connect for HL7v2 to FHIR. 3. Clinical review: EHR-native display; SMART-launched apps for external.
FHIR results reporting is a mature integration pattern. Get the resource linkages right and clinicians see complete, interpretable results.