biomarker

1. (medicine) A substance used as an indicator of a biological state, most commonly disease.Examples: "The goal of combining biomarkers is usually to increase the predictive power beyond that afforded by an individual molecular biomarker."; "“We are very interested in the concept of biomarkers, including digital biomarkers; in other words, the pattern of your accessing the internet may allow us to detect whether or not you are going to turn out to be vulnerable or not,” said Fineberg, although she admits at present this is just a theoretical idea."

2. (biology) Any measurable phenomenon that indicates the presence of life.