Ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEEs) are incorporated into hair as it grows. Analyzing hair samples can provide a retrospective window into an individual’s alcohol consumption over approximately 90 days, depending on the length of the hair sample. Laboratory analysis generates quantitative results, typically expressed in picograms per milligram (pg/mg) for both EtG and FAEEs. These results are often interpreted using established cutoff levels to assess chronic excessive alcohol use. Charts or tables may be used to categorize these levels, often differentiating between social drinking, moderate drinking, and heavy or chronic excessive drinking. For instance, an EtG level below a specific threshold might indicate abstinence or social drinking, while higher levels could suggest more frequent and substantial alcohol consumption.
This type of testing offers several advantages over traditional methods like blood or urine tests, which only provide a snapshot of recent alcohol use. It provides a longer-term perspective, making it valuable in situations where sustained abstinence is crucial, such as monitoring individuals in recovery programs, assessing compliance with legal mandates, or evaluating pre- and post-liver transplant patients. The development and refinement of these analytical techniques have enhanced the ability to detect patterns of alcohol consumption and provide more objective data for clinical and forensic purposes.
