Start with a small set
FHIR defines well over a hundred resources, but a typical hospital integration uses around a dozen. Learning those first makes the rest of the specification much easier. This list pairs well with FHIR vs HL7 v2.
The core resources
- ✓Patient — the person: identifiers (including ABHA), name, gender, date of birth, contact details.
- ✓Practitioner and Organization — clinicians and facilities, tied to registry identifiers.
- ✓Encounter — a visit or admission: when, where and with whom.
- ✓Condition — diagnoses and problems.
- ✓Observation — measurements such as vitals and lab values.
- ✓DiagnosticReport — a report grouping observations or documents, for example a lab or radiology report.
- ✓MedicationRequest — prescriptions and medication orders.
- ✓AllergyIntolerance — recorded allergies, critical for safety.
- ✓Composition and Bundle — a Composition structures a clinical document (such as a discharge summary) and a Bundle packages the resources together for exchange.
- ✓DocumentReference — pointers to scanned or binary documents.
- ✓Consent — records what the patient has agreed to.
How they connect
Think of a discharge summary as a Bundle containing a Composition that references a Patient, an Encounter, Conditions, MedicationRequests and DiagnosticReports. Every reference needs to resolve, otherwise validators and receiving systems will reject the bundle.
Common mistakes
- ✓Using free text where a coded value (SNOMED CT, LOINC) is expected.
- ✓Creating a new Patient resource for each visit instead of reusing identifiers.
- ✓Skipping validation until the end. Validate every bundle against the published profiles during development.
- ✓Losing units or reference ranges on Observations.
Where to go next
Map each resource to the tables in your HIS before writing code, and agree on which terminology systems you will use. The mapping document is the most valuable artefact in the project. See also why integration projects fail and the ABDM guide.
Frequently asked questions
Do we need to store data natively as FHIR?
No. Many hospitals keep their existing database and generate FHIR on demand through an integration layer.
Which terminologies are commonly used with FHIR in India?
SNOMED CT for clinical terms, LOINC for lab observations and local code sets where needed. Check the ABDM profiles for what is required.
How do we check that our FHIR is valid?
Use a FHIR validator against the relevant profiles as part of automated tests, not only at the end of the project.
Need help with this in your hospital?
Tell us your systems and your goal. We'll map it to a scoped plan.
Talk to our team →This guide is general information for engineering and planning purposes. It is not legal advice, and regulations and specifications change; confirm current requirements with the relevant authority or qualified counsel.
