Clinicians can use several biochemical measurements to objectively assess patients' current or past alcohol use. However, none of these currently available biomarkers-including measures of various liver enzymes and blood volume--are ideal. Several more experimental markers hold promise for measuring acute alcohol consumption and relapse. These include certain alcohol byproducts, such as acetaldehyde, ethyl glucuronide (EtG), and fatty acid ethyl esters (FAEE), as well as two measures of sialic acid, a carbohydrate that appears to be altered in alcoholics. Some progress has been made in finding markers that predict people's genetic predisposition to alcoholism, such as genetic differences in several neurotransmitters, including beta-endorphin and gamma-aminobutryic acid (GABA).