Direct Ethanol Biomarker Testing: PETH

Answers From the Lab

Several major medical organizations recommend routine screening for unhealthy alcohol use. In this test specific episode of the "Answers From the Lab" podcast, Paul Jannetto, Ph.D., describes Mayo Clinic Laboratories' new direct biomarker test for alcohol consumption, PETH. This blood test has a much longer window of detection than existing urine tests for alcohol use.

"Alcohol is the most commonly abused drug in the world, and excessive alcohol use is the leading preventable cause of death in the United States," Dr. Jannetto says. "Routine screening and behavioral intervention for alcohol misuse is one of the most cost-effective clinical preventive services."

The preferred screening approach for ethanol — the chemical term for alcohol — measures certain substances that the body produces when ethanol is metabolized. The direct ethanol metabolites  (i.e., ethyl glucuronide and ethyl sulfate) currently used for alcohol testing can be detected in urine for up to five days.

PETH measures a different alcohol metabolite, known as phosphatidylethanol (PEth), in whole blood. "This new biomarker gives a window of detection of approximately two to four weeks in blood. The window can be longer in individuals who chronically or excessively consume alcohol," Dr. Jannetto says.

Listen to learn more about how PETH provides enhanced screening for alcohol consumption.

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Useful information

This assay is designed to quantify two homologues of phosphatidylethanol (PEth) in whole blood collected in EDTA vacutainer tubes. The report is intended for use by physicians to verify abstinence or use of ethanol especially in liver transplant candidates/patients.

Specimen requirements

  • Specimen Type: Whole Blood
    • Frozen (Preferred) 21 days
    • Refrigerated 7 days
  • Container/Tube: Lavender Top (EDTA)
  • Specimen Volume: 1 mL
  • Specimen Minimum Volume: 0.5 mL

Performance information

Analytic time: 2 days

Days performed: Monday through Friday (8 a.m.)

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Barbara J. Toman

Barbara J. Toman is a Senior Communications Specialist at Mayo Clinic Laboratories. She is also the science writer for Mayo’s Neurosciences Update newsletter, which helps referring physicians to stay informed about Mayo’s treatment and research. Barbara has worked at Mayo Clinic since 2007. She enjoys international travel and cooking.