Health glyphs

The medical symbols opsinjs will not use, because an app that borrows the visual language of clinical authority is claiming something it has not earned.

Overview

There is a standard visual vocabulary for "medical": a cross, a stethoscope, a caduceus, a figure in a white coat, a pill, a syringe, an ECG trace. It is instantly legible, it is what every stock icon set offers under the search term "health", and opsinjs does not use any of it.

The reason is the same one that runs through the whole system. opsinjs presents health data to a layperson; it does not practise medicine, does not diagnose, does not triage, and confers no clinical status on the product that uses it. See Safety, scope and limitations. A symbol that says "clinician" is a claim of authority, and putting one next to a number changes how that number is read. A reading annotated with a stethoscope reads as a clinical finding; the same reading annotated with a heart outline reads as a measurement, which is what it is.

How it works

The excluded set, with the reason for each, because a ban without a reason is just a preference:

Symbol	Why not	Use instead
Red cross on white	Protected under the Geneva Conventions and their national implementing law; using it is a legal matter, not a design one	Nothing, because the concept it is reaching for is usually "urgent", which is a status
Any cross used to mean "medical"	Claims clinical authority; also carries specific religious and national meanings in different places	The glyph for the thing actually being measured
Caduceus or rod of Asclepius	Pure authority signalling, and widely confused with each other	Words
Stethoscope, white coat, clinician figure	Says "a doctor is involved"; usually one is not	The category glyph, or a person's own name
Syringe, needle, blood drop	Distressing to a large number of people, including many with the conditions the product is for	The name of the test, in words
Pill or capsule to mean "health"	Health is not medication; and to somebody managing a long-term condition the association is loaded	The specific concept: a dose, a reminder, a course
ECG trace as decoration	Implies a diagnostic reading where there is none; a decorative waveform is fabricated data	A real chart, or nothing
Tick, cross, thumbs-up, smiley beside a value	A verdict, delivered by a picture, with no source	Clinical status, in colour, icon and word

What the system uses instead. Category glyphs are drawn from the ordinary world: the object being measured, or the activity being recorded. A bed for sleep, a footprint for movement, a heart outline for heart rate. They are descriptive rather than authoritative, they are legible without medical knowledge, and they do not imply that anyone has interpreted anything.

The status glyphs are abstract, not medical: shapes that carry ordinal weight without borrowing meaning from anywhere. They are always accompanied by a colour and a word, so the glyph never has to be self-explanatory. That is what allows them to be abstract in the first place.

Emergency is a special case, and it is not a glyph problem. Where a product does need to tell somebody to seek immediate help, that is a screen with words, a phone number and a stated source, decided by the product's clinical governance. See Emergency and escalation. A red cross is not an escalation mechanism; it is a picture where a sentence should be.

Using it

Ask what the glyph is claiming. Every icon makes an implicit claim about who is speaking. A stethoscope claims a clinician. A caduceus claims a profession. A bed claims nothing at all, which is correct, because the product is reporting that somebody was asleep.

A blood-glucose result headed with a plain droplet-free category glyph and the metric's name in words, with the reading, its unit and who measured it.

Don’t

The same result headed with a stethoscope and a red cross. Nothing has been added to the reading. Without a word being written, a reader has been told that a clinician has looked at it.

Do not use a warning triangle as a status glyph by default. It is the strongest general-purpose alarm symbol most readers know, so spending it on the second of four levels leaves nothing above it. What each level's glyph is belongs to clinical status semantics.

Do not draw anatomy as decoration. An organ illustration used as a section header is a clinical image doing an ornamental job, and it will be read as diagnostic by somebody. Locating a symptom is one job that genuinely calls for a body diagram. Where that need is genuine, the diagram is a deliberate, specified surface with its own rules: Body diagrams.

Do not borrow a national health service's marks, colours or symbols. They signal endorsement, they are usually protected, and the endorsement is not real. The related content rule is on Official resources.

Tokens

This page constrains the icon mapping rather than owning tokens. The excluded set is a rule on Icon inventory, which is where a role resolves to a glyph, and it is the natural place to enforce mechanically.

This table has not been generated. It is produced by scripts/build-registry.mts. Run pnpm run generate and reload.

Nothing on this site types a measured number by hand, so an ungenerated table shows this rather than an example.

Accessibility impact

A symbol that implies authority is a comprehension problem, not just a regulatory one. Readers with low health literacy are the most likely to take a clinical-looking mark as evidence that a clinician has been involved, and they are the readers the whole system is written for.
Needles, blood and clinical imagery cause real distress. Needle phobia is common, and people managing long-term conditions have accumulated associations a design system cannot see. An icon that makes somebody close the app has prevented them from reading their own data.
Abstract status glyphs are more accessible than medical ones, because they are learned in one place and always accompanied by a word, rather than depending on prior knowledge the reader may not have.
Cultural legibility varies enormously and silently. Crosses, colours and gestures do not mean the same thing everywhere, and a reader who misreads a glyph has no way to ask.
None of this removes the need for a text alternative. Every meaningful glyph still carries a name; choosing a better symbol is not a substitute for labelling it.

Icon inventory is the mapping these rules constrain.
Safety, scope and limitations says what opsinjs is and is not, which is the argument underneath this page.
Imagery → Illustration style covers the same question one level up, for pictures rather than glyphs.