Urine Alcohol Metabolites (EtG/EtS): Detection Windows & Interpretation

Ethyl Glucuronide (EtG) & Ethyl Sulfate (EtS)

Direct, stable, non-volatile metabolites of ethanol. More sensitive/specific than urine ethanol (which reflects recent bladder alcohol).

Approximate Detection Windows (After Last Drink)

Scenario	EtG (hrs/days)	EtS (hrs)
Single occasion (1–4 drinks)	Up to 24–48h (can detect to 72–80h in some)	24–36h
Binge / Heavy episode	48–96h (up to 5–7 days reported)	48–72h
Chronic heavy use	Days to 1–2 weeks (accumulation)	Variable, up to several days

Key Variables Affecting Detection

• Urine volume/concentration (dilute urine → lower concentration, but total excretion similar; creatinine correction helps).
• Age, BMI, liver function, medications (some induce/inhibit UGT/SULT).
• Age of specimen (bacterial degradation of EtG if not refrigerated/frozen).

Interpretation Caveats

• EtG > EtS sensitivity. EtS more specific (less false + from bacterial synthesis).
• Incidental exposure (hand sanitizer, mouthwash, foods, medications) can yield low-level EtG (<500 ng/mL). Cutoffs matter: SAMHSA suggests ≥500 ng/mL for recent drinking; ≥1000 ng/mL more specific.
• Not a measure of impairment – only recent exposure.

Clinical / Forensic Use

• Abstinence monitoring (treatment programs, professional monitoring, transplant, legal).
• Complement to self-report, breath, blood.

If You're Being Tested

Abstinence is the only reliable way to test negative. "Flushing" (excess water) risks dilute specimen flag. Consult your program counselor or an addiction medicine physician for guidance.