Key points
- Match the format to the data. Structured facts travel as data, and signed documents travel in their original form.
- FHIR, from HL7, exchanges health data as resources, and its Bulk Data guide covers export for whole groups of patients.12
- CDA keeps a clinical document whole, attributable and human readable, which suits letters and summaries.3
- The US export criterion sets no single format, and every export must be computable and come with documentation of its format.4
- Only 8% of 8,122 US family physicians reported an ideal experience receiving outside test results.5
Summary
Ask for structured data in FHIR where the receiving system reads it, signed letters and notes in their original form as CDA or PDF, and flat lists such as appointments and invoices in CSV, each with documentation of its format.
The next clinician opens the full history on day one, with clean structured data and every signed letter intact. The formats you write into the contract today make that happen.
See it in your clinicThirty minutes on your own patients and doctors.
Request a demoSee a signed note and letter exported from wai and opened in another system.
| Format | Best for | Keeps | Loses | What to ask |
|---|---|---|---|---|
| FHIR R4 | Allergies, medications, problems, results, appointments | Structure and coded meaning | Layout of the original document | Which resources, which version, bulk export for all patients |
| CDA | Letters, summaries, signed clinical documents | The whole document, its author and context | Little, if the receiver reads CDA | Which document types export as CDA |
| Signed notes and letters as a faithful copy | What the clinician saw and signed | Machine readability, unless computable | Is the PDF text based and searchable | |
| CSV | Appointments, invoices, contacts, price lists | Simple rows and columns | Documents, signatures and nested data | Column definitions supplied with the file |
| Audit log export | Messages, drafts, approvals and signatures | Who did what, and when | Nothing, if complete | Every event with a name and a time |
| Format documentation | Every export | The ability of the next system to read it | Everything, if missing | A link to the format documentation with each export |
Match the format to the data
Structured facts such as allergies and results, documents such as signed letters, and events such as approvals in the audit log each travel best in their own format.
In a 2025 survey of 8,122 US family physicians, 8% reported an ideal experience receiving test results from outside hospitals or health systems.5 Across OECD members, 38% of countries have no clinical standards or vendor certification for record systems.6 Formats written into the contract keep the clinic's own records usable whatever the wider picture.
FHIR, for data that moves between systems
FHIR, Fast Healthcare Interoperability Resources, is the HL7 standard for exchanging healthcare information electronically.1 Its unit is the resource, such as a patient, an observation or a medication, each with common metadata and a human readable part.1 Release 4, version 4.0.1, is the release wai is built to connect over, and HL7 has since published Release 5.1
HL7's Bulk Data guide describes exporting large volumes of FHIR data on a group of patients, for example from a record system to a partner organisation.2 Ask which FHIR resources export, in which version, and whether a bulk export covers all patients.
CDA, for documents that must stay whole
The HL7 Clinical Document Architecture is a standard for exchanging clinical documents between providers and patients.3 HL7 defines a clinical document by six characteristics, persistence, stewardship, potential for authentication, context, wholeness and human readability, and a CDA document carries a readable body with structured data alongside.3
The receiving clinician sees what the author signed, in the context it was written.
PDF and CSV, each for one job
PDF opens anywhere and suits signed letters and notes as a faithful copy. Ask for text-based PDFs, because the US export criterion accepts PDF only where it is computable.4
CSV suits flat lists such as appointments, invoices and contact details, and almost any system imports it. Send documents, signatures and nested data such as a medication with its dose history in FHIR or CDA alongside it.
What the US export rule asks for
ONC criterion 170.315(b)(10) requires certified systems to export all of one patient's electronic health information on demand and all information for the patient population.4 ONC leaves transport methods and data standards open, and requires the export to be electronic and computable with a publicly accessible link to its format.4
Ask for format documentation with every export, in any country. The contract terms that make it binding are in the clinic software exit plan.
How records leave wai
Signed notes and letters export from wai into any system, and the clinic can export the event log of every message, draft, approval and signature.78
wai is built to connect to two large US hospital records systems, both listed on the integrations page. We set up your clinic's connection with you. It reads a patient's history over FHIR R4 to prepare the clinician before the visit.7
Where to start
Sort what the clinic holds into structured facts, documents and events, and write the format for each into the contract using the table.
Run a test export from the current system this month and open it in a second system. Fix whatever does not arrive intact first. The wider move is in the switching checklist.
Bring a sample of your current records and see notes and letters leave wai and open in another system.
Frequently asked questions
When should we use FHIR and when CDA?
When is a PDF export enough?
For signed letters and notes as a faithful copy. Structured data needs FHIR or CSV, and US certification accepts PDF only where it is computable.4
Does every export need documentation?
Yes. The US export criterion requires a publicly accessible link to the format with every export, and the practice works in any country.4
Can wai export our records into another system?
Can wai read from a large US hospital records system?
wai is built to connect to two large US hospital records systems, both listed on the integrations page. We set up your clinic's connection with you. It reads patient history over FHIR R4.7
What about images and scans?
Ask whether images export as files or as links, and where the originals sit. ONC guidance notes that where a system stores only links to images, only those links must be exported.4
Sources
- 1HL7 International, 2019FHIR R4 overview, version 4.0.1Read 14 October 2026Read source
- 2HL7 InternationalBulk Data Access Implementation Guide, STU 2Read 14 October 2026Read source
- 3HL7 InternationalClinical Document Architecture (CDA) Release 2, product briefRead 14 October 2026Read source
- 4Office of the National Coordinator for Health IT (ASTP/ONC), 2025Electronic health information export, 170.315(b)(10), Certification Companion GuideRead 14 October 2026Read source
- 5JAMA Network Open, Everson and colleagues, 2025EHR Interoperability Experiences Reported by Family Physicians (PubMed abstract)Read 14 October 2026Read source
- 6OECD, 2023Health at a Glance 2023, OECD IndicatorsRead 14 October 2026Read source
- 7wai, 2026wai integrationsRead 14 October 2026Read source
- 8wai, 2026Security at waiRead 14 October 2026Read source
Every note and letter readable in the next system on day one.
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