Ethyl Glucuronide (EtG) and Ethyl Sulfate (EtS) are direct biomarkers or metabolites of ethanol, and they are called that because they are direct products of the metabolism of ethanol. Although most alcohol that is consumed is metabolized by oxidative processes in the liver, a very small amount is broken down non-oxidatively, creating EtG and EtS and these biomarkers can be measured for a longer period of time than ethanol itself can be.