A biomarker is anything measurable in your body that reflects how it’s working, a molecule in your blood, a cell count, a hormone, an enzyme. Each one is a small window onto a larger system.
Why the number needs a range
A value on its own means little. It’s read against a reference range, the span most healthy people fall in, which varies by lab, method, age, and sex. That’s why the same result can look different on two reports.