Interoperability

Medical Device Interoperability

Purpose

Enable safe and standards-aligned interoperability: HL7 FHIR/IHE profiles, data formats, terminology mapping, and API design for medical data exchange.

When to Apply

• Designing or updating device APIs, data exchange, or integrations with HIS/EMR/cloud.
• Handling PHI or clinical decisions based on exchanged data.

Requirements (testable)

1. Standards Use: Prefer established standards (HL7 FHIR, HL7 v2 where applicable, IHE profiles) for relevant data flows; document conformance. Rationale: interoperability and clarity.
2. Terminology: Use standard vocabularies (SNOMED CT, LOINC) for clinical concepts; map device codes to standard codes. Rationale: semantic consistency.
3. Data Integrity: Validate messages (schema/length/range); apply checksums/hashes over payloads where appropriate; reject/flag invalid data. Rationale: correctness.
4. Security & Privacy: Protect PHI with TLS 1.3+; enforce authz (scopes/roles); log access; minimize data shared. Rationale: confidentiality/integrity.
5. Error Handling: Provide clear, standard error responses; fail safe; no silent truncation. Rationale: predictable integration.
6. Traceability: Log message IDs, timestamps, and correlation IDs; link to requirements/tests; keep audit for safety-relevant exchanges. Rationale: accountability.
7. Interop Risks: Document interop-related hazards (misinterpretation, time sync, version mismatch) and mitigations. Rationale: safety.

Recommended Practices

• Provide versioned APIs and explicit capability statements (e.g., FHIR CapabilityStatement).
• Time-sync devices (NTP/PTP) to avoid timestamp drift in clinical workflows.
• Use contract tests against partner systems; include negative cases.
• Avoid custom extensions unless necessary; document them clearly.

Patterns

FHIR-like JSON validation (pseudo):

# REQ-INTOP-VALID-01; TEST-INTOP-04
def validate_observation(obs: dict) -> bool:
    required = ["resourceType", "status", "code", "subject", "effectiveDateTime"]
    if obs.get("resourceType") != "Observation":
        return False
    return all(k in obs for k in required)

Terminology mapping table (YAML):

# REQ-INTOP-TERM-02
device_code: FLOW_RATE
loinc: 8310-5
display: Infusion flow rate

Error response:

// REQ-INTOP-ERR-03; TEST-INTOP-07
{ "error": "invalid-parameter", "detail": "missing code" }

Anti-Patterns (risks)

• Custom proprietary formats without mapping -> risk: misinterpretation by HIS/EMR.
• Sending PHI over plaintext or weak TLS -> risk: data breach.
• Silent acceptance of invalid messages -> risk: wrong clinical decisions.
• No time sync -> risk: misleading timestamps in therapy/diagnostics.

Verification Checklist

• Standards selected and documented; conformance statements present.
• Terminology mapped to SNOMED/LOINC (or applicable); mappings versioned.
• Message validation implemented; invalid data rejected/logged.
• TLS 1.3+ and authz enforced; PHI minimized; access logged.
• Error responses clear and standard; no silent truncation.
• Interop hazards documented with mitigations/tests.
• Time synchronization implemented and monitored.

Traceability

• Requirements REQ-INTOP-### linked to contract/interop tests TEST-INTOP-###; logs maintain correlation IDs for message tracing.

References

• HL7 FHIR R4/R5; HL7 v2 where applicable.
• IHE profiles relevant to devices (e.g., PCD-01, DEC).
• FDA interoperability guidance (2017).
• IEC 62304/ISO 14971 for risk integration.

Changelog

• 1.0.0 (2026-01-04): Initial interoperability skill with standards use, validation, terminology, and security guidance.

Audit History

• 2026-01-04: Audit performed. Verified:
  • HL7 FHIR R4/R5 references accurate
  • IHE profiles (PCD-01, DEC) correctly mentioned
  • FDA interoperability guidance (2017) reference verified
  • SNOMED CT and LOINC terminology references appropriate