How are direct alcohol biomarkers used to detect the toxic effects of alcohol?

Updated: Nov 27, 2018
  • Author: Warren Thompson, MD, FACP; Chief Editor: Glen L Xiong, MD  more...
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Direct alcohol biomarkers are analytes of alcohol metabolism. [4]

  • Direct alcohol biomarkers include alcohol itself and ethyl glucuronide (EtG). [4]

  • A blood alcohol level might be helpful in the office if the patient appears intoxicated but is denying alcohol abuse. A blood alcohol level in excess of 300 mg/dL, a blood alcohol level of greater than 150 mg/dL without gross evidence of intoxication, or a blood alcohol level of greater than 100 mg/dL upon routine examination indicates alcoholism with a high degree of reliability. The short half-life of alcohol limits its use widely as a biomarker. [6] As the blood alcohol level detects alcohol intake in the previous few hours, it is not necessarily a good indicator of chronic excessive drinking. [5]

  • EtG is a minor, nonoxidative, water-soluble, stable, and direct metabolite of alcohol that is formed by the conjugation of ethanol with activated glucoronic acid. [40, 6, 5] Shortly after alcohol intake, even in small amounts, EtG becomes positive. [5] After complete cessation of alcohol intake, EtG can be detected in urine for up to 5 days after heavy binge drinking [7, 6] , making EtG an important biomarker of recent alcohol consumption. [5] A 2006 report by the Substance Abuse and Mental Health Services Administration states that the use of EtG should be considered as a potential valuable clinical tool, but the use of EtG in forensic settings is premature. [4]

  • Other direct alcohol biomarkers of emerging interest include acetaldehyde, fatty acid ethyl esters (FAEE), Ethyl Sulfate (EtS), and Phosphatidylethanol (PEth). [4, 7]

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