Pregnanediol Glucuronide, C27H44O8, also known as PDG (5β-Pregnan-3a, 20a-diol 3-glucosiduronate) is the major metabolite of progesterone. Progesterone is an essential regulator of human female reproductive function in the uterus, ovary, mammary gland and brain, and plays an important role in non-reproductive tissues such as the cardiovascular system, bone and the central nervous system. BioVision’s PDG ELISA kit is a competitive ELISA assay for the quantitative measurement of PDG in urine and fecal samples. Standards or diluted samples are pipetted into a clear microtiter plate coated with an antibody to capture rabbit antibodies. A PDG-peroxidase conjugate is added to the standards and samples in the wells. The binding reaction is initiated by the addition of a polyclonal antibody to PDG to each well. After incubation the plate is washed and substrate is added. The substrate reacts with the bound PDG-peroxidase conjugate. After a short incubation, the reaction is stopped and the intensity of the generated color is detected in a microtiter plate reader capable of measuring 450 nm wavelength.