Glossary · Biology
Biomarker
In short
A biomarker is a measurable characteristic that reveals something about a condition in the body — a blood value, an imaging finding, a reading from a wearable. It can indicate a risk, help detect a disease or track the course of a treatment.
Whether a biomarker is useful depends on its task. A good risk marker reliably predicts disease. But it does not follow that lowering the marker helps. That requires studies in which a treatment that changes the marker also improves the outcome — only then is it useful as a surrogate marker.
For self-trackers, measurement precision comes on top: if a value fluctuates from day to day more than the effect being looked for, a single measurement says little.
A marker predicts something — that does not mean it should be treated.
Where this comes up in the fact checks
- Coronary calcium score – A strong risk marker, recommended by guidelines when risk is uncertain; whether screening prolongs life is open.
- ApoB test – Counts the cholesterol transport particles and in part predicts heart risk better than LDL.
- Epigenetic age test – Methylation clocks predict disease and mortality in large studies; as a personal measurement they have limits.
Sources
Related terms: Surrogate marker · Epigenetic clock · HbA1c (long-term blood sugar) · LDL and ApoB
Information only, not medical advice. The BK-Score is a subjective assessment according to disclosed rules – not a scientific evaluation. Scoring rules