- Medicine a. A physiological substance, such as human chorionic gonadotropin or alpha-fetoprotein, that when present in abnormal amounts in the serum may indicate the presence of disease, as that caused by a malignancy.b. A specific physical trait used to measure or indicate the effects or progress of a disease or condition: Biomarkers of aging include thinning of the hair. Also called biosignature .
- See biosignature .
bio- +"Ž marker