Indicator Explainer
Selenium
A nonmetallic chemical element found in trace amounts in human body. Selenium primarily occurs in vivo as selenocompounds, mostly selenoproteins such as glutathione peroxidase and thioredoxin reductase (enzymes responsible for detoxification). Alone or in combination with Vitamin E, selenocompounds act as antioxidants. These agents scavenge free radicals; prevent blood clots by inhibiting platelet aggregation; strengthen the immune system; and have been shown, in some instances, to inhibit chromosomal damage and mutations. Exhibiting chemopreventive activity, selenocompounds also inhibit the induction of protein kinase C.
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Source: National Cancer Institute, NCI Thesaurus 26.09d, C825. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-19. No individual clinical interpretation or human reviewer is asserted.
Reading results
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.