For other meanings, see the disambiguation page Marker

Biomarker is a substance used as an indicator of a biologic state. It may mean the following:

• It can be any kind of molecule indicating the existence (past or present) of living organisms. In particular, in the fields of geology and astrobiology biomarkers are also know as biosignatures. The term is also used to describe biological involvement in the generation of petroleum (see Biomarker (petroleum)).

• In medicine, a biomarker can be a substance that is introduced in an organism as a means to examine organ function or other aspects of health. For example, rubidium chloride is used as a radioactive isotope to evaluate perfusion of heart muscle.

• In biology and medicine, a biomarker can be a substance whose detection indicates a particular disease state (for example, the presence of an antibody may indicate an infection). Such a biomarker can be native to the body. A biomarker can also be used to indicate exposure to various environmental substances in epidemiology and toxicology. In these cases, the biomarker may be the external substance itself (e.g. asbestos particles or NNK from tobacco), or a variant of the external substance processed by the body (a metabolite).

• In genetics, a biomarker (identified as genetic marker) is a fragment of DNA sequence that is associated with, changes susceptibility to disease or causes disease.

See also molecular marker, biomarker discovery.

Biomarker | Marqueur biologique