Estriol ELISA kits are assays designed to detect the weak estrogen hormone estriol. It is one of the main endogenous estrogens, and a minor female sex hormone. It is produced in large amounts by the placenta and is the predominant estrogen in the blood during pregnancy. Estriol levels are used as an indicator of a normal pregnancy. It can be used as a synthetic medication in hormone therapy, especially for menopause. Visit the supplier page for more information about detection range and reactivity.