How Zaynix Health handles your clinical data.

01

Terminology architecture.

The platform is built on four international clinical terminology standards. None of them are aspirational — every record that lands in the trusted longitudinal record is normalised against them at write time.

LOINC — laboratory observations

Every blood marker that reaches the longitudinal chart is mapped to a Logical Observation Identifiers Names and Codes (LOINC) concept. LOINC is the international standard for laboratory tests and clinical observations. The mapping is what makes an HbA1c on a Medichecks panel comparable to an HbA1c on an NHS pathology report two years later, even though the panels were ordered, drawn, and reported by different organisations.

The set of LOINC concepts the platform recognises at first pass includes the following common markers — codes shown verbatim:

Markers outside this set are still ingested and surfaced — but they go through the platform's flexible-extraction layer first, where they're either matched to an existing LOINC concept with a confidence score or routed to a patient-confirmation workflow before they enter the trusted record.

SNOMED CT UK — clinical concepts

Clinical concepts — diagnoses, allergens, procedures, findings — resolve against SNOMED CT, UK Edition. SNOMED CT is the terminology already used across NHS systems for clinical content; the UK Edition adds UK-specific extensions on top of the international release. The platform uses concept IDs (numeric) and preferred terms (human-readable) from the same hierarchy NHS systems use, so a diagnosis written in Zaynix is recognisable to any NHS-aligned system on export.

SNOMED's hierarchical structure also enables real safety checks. Penicillin (SCT 764146007) and amoxicillin (SCT 372687004) don't share a string — but amoxicillin is a SNOMED descendant of penicillin. The platform calls the $subsumes operation against the NHS Terminology Server to detect this kind of cross-reactivity automatically when a clinician adds an amoxicillin prescription to a patient with a recorded penicillin allergy.

NHS DM+D — medicines and devices

Medications are resolved against the NHS dictionary of medicines and devices (DM+D) — the same dictionary NHS prescribing systems use. DM+D gives every drug a stable identifier, a preferred name, and a route through brand → generic → ingredient that lets the platform reconcile the same medication recorded under different names across different documents over time.

UCUM — units of measure

Units are handled explicitly via the Unified Code for Units of Measure (UCUM). An HbA1c reported as mmol/mol from one lab and % from another resolves to a comparable value on the same chart. Cholesterol in mmol/L from a UK lab and mg/dL from a US private panel are converted at read time, not at write time, so the original source value is always recoverable.

02

Terminology servers.

Terminology mapping isn't done from a hand-curated lookup table. It's done against the same FHIR terminology servers the NHS and the international LOINC community publish.

NHS Terminology Server — SNOMED CT UK

SNOMED CT UK lookups are served by the NHS Terminology Server via its FHIR endpoint, authenticated with OAuth2. When a clinician adds an allergen, condition, or procedure, the platform calls the FHIR $expand or $lookup operation, retrieves the preferred term and semantic tag, and writes both onto the record alongside the concept ID. The same server provides the $subsumes operation that powers drug-allergy cross-reactivity checks.

Regenstrief LOINC FHIR — laboratory observations

LOINC concepts for blood markers are resolved against the Regenstrief LOINC FHIR server. Marker names are normalised first — including UK→US spelling normalisation (haemoglobin → hemoglobin) — before search, so a UK pathology PDF that uses British spelling still resolves to the same LOINC concept as a US lab.

Cache-per-concept strategy

Every terminology lookup is cached at the concept level. The first time a clinic resolves "Penicillin" to SCT 764146007 via the NHS server, that mapping is written to the local terminology cache. Every subsequent allergen recorded as "Penicillin" — across the same clinic, across other clinics — uses the cached entry. Terminology service availability isn't on the hot path of routine clinical use.

Disambiguation when the LLM can't pick one

When the terminology server returns multiple candidates that scoring can't narrow down with confidence, the platform doesn't guess. The record is flagged with an amber "possible matches" indicator and the patient is asked to pick the right concept from a short list. The decision is then written to the audit log and used to extend the cache, so the same ambiguity doesn't surface twice.

03

Provenance and audit.

Source-document linking

Every extracted value links back to the source document it came from. A clinician viewing a marker on a longitudinal chart can click through to the original PDF — the value, its reference range, and the lab's reported units, exactly as they appeared on the report. You will not see a number on a chart whose source you cannot inspect.

Confidence scoring

Each extraction is scored with a confidence value. High-confidence extractions — clean PDF text, recognised lab vendor, standard layout — enter the trusted record immediately. Lower-confidence extractions — image-only PDFs, unfamiliar layouts, ambiguous units — are held for patient confirmation.

Deferred-items workflow

Held items are surfaced in a patient-facing review queue, not silently dropped or auto-accepted. The patient sees the extracted value, the source document it came from, and the platform's best guess at the LOINC or SNOMED mapping. They confirm, correct, or reject. Their decision is logged.

Audit logging

Every read, write, edit, and confirmation against the patient record is written to an internal audit log with the actor, the action, the resource, and a timestamp. Patients have a right to request a copy of their own audit log under UK GDPR Article 15.

04

AI usage disclosure.

AI is used where it adds value to clinical reasoning. It is not used to make decisions about patients without clinician involvement, and every AI-generated output in the platform carries an "AI used here" badge that links to this page. The disclosure that follows is the plain-English version of what is also captured for EU AI Act Article 50 compliance.

Where AI is used

• ·Document parsing — extracting structured values from uploaded lab PDFs, clinical letters, and images.
• ·Biomarker interpretation — generating descriptive narratives about a marker's relationship to its reference range, on clinician request.
• ·Terminology disambiguation — when scoring can't narrow a SNOMED or LOINC match, the AI proposes the most likely candidate for the patient to review and confirm.
• ·Drug-name classification and allergy cross-reactivity reasoning — paired with the deterministic SNOMED $subsumes check, not as a replacement for it.

What the platform never does with AI

• ·Nevertrains AI models on patient data. Not ours, not the AI provider's, not anyone's.
• ·Neveruses AI to make automated decisions about patients within the meaning of UK GDPR Article 22. AI output is advisory.
• ·Nevercalls the AI without explicit consent that the user has opted in and not revoked.
• ·Neverhides AI output. Every piece of AI-generated content carries an "AI used here" badge.
• ·Neversells data, to an AI provider or anyone else.

What the platform always does with AI

• ·Alwaysrecords every AI call in an internal audit log — model name, token counts, consent verification. Patients have a right to a copy of their entries.
• ·Alwaysmarks every AI-generated record in the GDPR data export with an ai_generated flag so the patient can see which parts of their data came from AI.
• ·Alwayskeeps the non-AI version of every feature fully usable. AI is an enhancement, not a dependency.
• ·Alwaystreats human oversight as the default. Any AI output that touches a medical topic is clearly marked as informational and carries a disclaimer that it must not replace clinical advice.

05

Reference range handling.

Reference ranges are stored alongside each value, not derived from a platform-wide default. When a Medichecks panel reports HbA1c with a range of 20–42 mmol/mol and an NHS GP panel reports it with <42 mmol/mol, both are preserved with their original framing. The chart shows the patient's value with the range that was actually in effect for that draw, not a retroactively re-applied platform reference range.

UK pathology unit conventions are first-class. Cholesterol is mmol/L by default; testosterone is nmol/L; HbA1c is mmol/mol (with the % equivalent computed on read for comparison with international panels). Vendor-specific reference profiles are stored per lab, so a Randox cardiology panel's slightly different LDL cut-points don't get flattened into the platform's average.

When a marker is reported in units the platform doesn't have a UCUM conversion for, it is preserved as-is and shown on the chart with a unit annotation rather than silently converted. The platform will never invent a value.

06

Identifiers in use.

These are the concrete identifiers that land in the patient record. They are not aspirational examples.

• ·SNOMED CT UK 764146007 — penicillin (substance), used to anchor allergy records.
• ·SNOMED CT UK 372687004 — amoxicillin, a SNOMED descendant of penicillin (cross-reactivity flagged by $subsumes).
• ·LOINC 4548-4 — haemoglobin A1c / total haemoglobin in blood (HbA1c).
• ·LOINC 718-7 — haemoglobin (mass/volume) in blood.
• ·UCUM mmol/mol ↔ % — HbA1c unit conversion held internally; both forms surfaced on the chart.

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