Biomarker and condition associations
A clinical-test result is one of the five entity kinds Evagene's correlation graph connects. The graph records which laboratory results are educationally associated with which conditions — and, crucially, qualifies those edges by whether the result is low or high. This page works through how those clinical-test edges are modelled, using the iron studies as the example.
Educational reference data. These associations teach which laboratory results tend to accompany which conditions. They are not a diagnostic rule, they produce no risk number, and they assert nothing about any individual. The presence of an association in the graph never means a person has the condition.
Three ways a test result relates to a condition
Clinical-test edges use three of the graph's eight relationship terms, which keep the nature of the association explicit:
biomarker— the result acts as a laboratory marker of the condition. A persistently raised fasting glucose and type 2 diabetes; a high transferrin saturation and hereditary haemochromatosis.associated_finding— the result commonly accompanies the condition without being its defining marker. A low mean cell haemoglobin alongside iron-deficiency anaemia; a low vitamin B12 alongside coeliac disease.risk_association— the result reflects a factor associated with a raised likelihood of the condition. Low iron stores, shown by a low ferritin, and restless legs syndrome.
Each edge also carries an optional strength (strong, moderate, weak) and a short, neutral note explaining the association in educational terms.
Status-qualified edges: low means something different from high
The same test name points to different conditions depending on direction, so a clinical-test endpoint can carry a status — abnormal_low or abnormal_high. The graph then surfaces the right associations for each direction. Ferritin is the headline case:
Ferritin — low
Depleted iron stores: associated with iron-deficiency anaemia (biomarker, strong) and restless legs syndrome (risk association, moderate).
Ferritin — high
Iron overload: associated with hereditary haemochromatosis (biomarker, strong), particularly alongside a high transferrin saturation.
A test that is recorded but not marked low or high surfaces only the associations that hold regardless of direction. Some tests are intrinsically direction-free — a haemoglobin electrophoresis or a sickle-cell screen is associated with the haemoglobinopathies as a finding, not as a "low" or "high" value — and those edges carry no status at all.
A worked teaching example: the iron studies
The iron panel is a clean illustration of why direction matters, and of how the graph lays out a differential for a learner to explore. Recorded with their direction, these results pull apart two conditions that both touch iron metabolism:
| Result | Direction | Educationally associated with |
|---|---|---|
| Ferritin | low | Iron-deficiency anaemia; restless legs syndrome |
| Transferrin saturation | low | Iron-deficiency anaemia |
| TIBC | high | Iron-deficiency anaemia |
| Mean cell volume (MCV) | low | Iron-deficiency anaemia; beta thalassaemia |
| Ferritin | high | Hereditary haemochromatosis |
| Transferrin saturation | high | Hereditary haemochromatosis |
A low MCV pointing at both iron-deficiency anaemia and beta thalassaemia is exactly the kind of overlap a graph is good at teaching: two conditions that share a microcytic picture, surfaced side by side so a learner can read the notes and explore the difference. The graph lays out the associations; it does not decide between them, and it issues no recommendation about what to do next.
How it appears in the editor
When a ferritin result is recorded on an individual and marked low, the Related concepts panel groups its suggestions under "Because Ferritin (low) is recorded:" and offers the low-ferritin associations. Mark the same test high and the panel offers the haemochromatosis association instead. Each suggestion can be ticked onto the individual or left alone — the user does the asserting, never the graph. The "explore any concept" search lets a learner pull up a test's associations without recording it on anyone at all.
Boundaries
- These edges are educational associations, not diagnostic criteria and not decision rules.
- They produce no risk number and make no screening, referral, or treatment recommendation.
- An association appearing for a recorded result never asserts that the individual has the associated condition.
- Evagene is an academic, research, and educational pedigree modelling platform — not a medical device, not clinical decision support, and not a diagnostic or screening tool.
Further reading
- Related Concepts Explorer — the full correlation graph and how the editor panel works.
- Gene and shared-gene associations — the auto-derived genetic edges.
- A genetics concept map for teaching.
- Haemoglobin and development genetics — background on the haemoglobinopathies referenced above.