Evidence quality

Biomarker

A measurable biological signal used to indicate a process, exposure, disease or response.

What it means

Definition

Biomarker. Biomarkers can help detect mechanisms or monitor response, but they are not always validated surrogates for real outcomes. Headlines often overinterpret biomarker changes as proven health benefit.

What it can tell you

It can distinguish indirect biological signals from outcomes that matter directly to patients.

What it cannot tell you

It cannot assume a marker change will translate into symptom, function or survival benefit.

Headline trap

Why this matters in headlines

An inflammatory marker falling after a supplement does not necessarily prove fewer illnesses.