This book is the practitioner introduction to the WIA-MED-020 Wearable Health Monitoring standard. It walks through the four-phase architecture (Data Format, API Interface, Federation Protocol, Integration) with the design rationale behind each phase, and shows how a vendor cloud, hospital RPM platform, EHR bridge, or research aggregator implements its side of the standard.
The dominant pattern today is vendor lock-in: an Apple Watch user, a Fitbit user, and a Withings user cannot present a single coherent data view to a clinician without manual export-import cycles. The clinician sees three vendor dashboards instead of one continuous physiological narrative.
WIA-MED-020 collapses the three vendor surfaces into one open wire format so that data from any conformant device can flow to any conformant clinician dashboard, EHR system, or research platform without vendor-specific integration. The patient remains the binding identifier; vendor account IDs become internal mappings.
A core design decision of the standard is the explicit clinical_grade flag on every device record. Most consumer wearable formats do not distinguish a fitness-tracker estimate of resting heart rate from an FDA-cleared continuous ECG patch. The standard requires the distinction so that clinical decisions can be made on appropriate evidence.
When clinical_grade: true, the device record MUST carry a regulatory-clearance number (FDA 510(k), EU CE-MDR, KFDA approval). Hosts MUST refuse claims without a valid reference. This creates a hard wall between consumer-grade and clinical-grade signals while letting both categories share the same wire format.
WIA-MED-020 composes with WIA-OMNI-API for credentials, WIA-AIR-SHIELD for transport hardening, WIA-INTENT for clinician intent lowering, WIA-ACCESSIBILITY for patient and clinician accommodations, and WIA Vital Sign Streaming for high-rate continuous waveforms. The composition is intentional: each WIA standard does one thing, and the family composes for full clinical workflows without any one standard becoming a kitchen sink.
This chapter participates in the WIA-MED-020 8-chapter survey. Each chapter is intended to be readable standalone, but together they map the full surface of the standard. The Phase numbering used throughout (Phase 1 / 2 / 3 / 4) refers to the four-document specification — Chapter 4 covers Phase 1, Chapter 5 covers Phase 2, Chapter 6 covers Phase 3, Chapter 7 covers Phase 4.
https://github.com/WIA-Official/wia-wearable-health-conformance is the single source of truth. When this book and the test suite disagree, the test suite wins.wia/wearable-health-host:1.0.0 implements every Phase 2 endpoint with mock data; integrators exercise their bridge against it before going to production.cli/wearable-health.sh ships sample envelope generators (validate, device, measurement, alert, consent, info subcommands) so an implementer can produce conformant payloads without hand-rolling JSON.Every choice in this standard is filtered through the question: "does this make wearable data more useful for the patient and their care team, or just easier for vendors to ship?" When the two conflict, the patient and care team win. That is why the standard mandates explicit patient consent for cross-host data flow, refuses to accept clinical-grade claims without regulatory clearance, and requires implementations to surface calibration provenance so that clinicians can verify the source quality of every measurement they make decisions on.