Ethyl glucuronide (EtG) in hair

This test measures ethyl glucuronide, a direct marker of alcohol consumption, in a small sample of hair. It is often ordered to show whether someone has used alcohol over roughly the past 90 days, supporting substance use treatment, workplace or legal monitoring, and personal recovery goals.

Your healthcare provider may order this test if they suspect chronic alcohol misuse, need to verify sobriety for legal or employment reasons, or evaluate long-term drinking patterns. Hair provides a timeline of alcohol exposure, unlike blood or urine tests that show only recent use.

As hair grows, alcohol byproducts such as ethyl glucuronide become deposited into the growing strand and remain locked in place. A laboratory analyzes the sample in segments, so results reflect drinking patterns over weeks to months rather than only the most recent few days.

Hair is collected and analyzed using a high-performance liquid chromatography (hplc) method to detect ethyl glucuronide. This metabolite forms when alcohol breaks down in the body and is stored in hair follicles over time.

A trained collector cuts a small amount of hair, usually from the crown of the head, as close to the scalp as possible. If head hair is unavailable or too short, body hair from the chest, arm, leg, or underarm may be collected instead, and the site is documented.

You’ll need to provide a hair sample, typically a small section from the scalp. The test focuses on the root end, where metabolites accumulate. No fasting is required.

Collection takes only a few minutes and is painless. You may feel a slight tug as the hair is cut, but nothing is pulled from the root. The collector seals the sample in a labeled envelope, and results are typically released within several business days.

Results take several days to weeks to process. You’ll receive a report indicating the presence or absence of ethyl glucuronide, but not specific alcohol consumption amounts.