What does EtG stand for?
EtG stands for ethyl glucuronide. The liver forms it when ethanol is joined with glucuronic acid. Only a small portion of consumed alcohol becomes EtG, but sensitive laboratory methods can detect that metabolite after ethanol has cleared.
How a urine EtG test works
A screening immunoassay or laboratory method measures EtG in nanograms per milliliter (ng/mL). A result at or above the selected cutoff may be reported as positive. Laboratories may use confirmation testing and may also measure ethyl sulfate (EtS), another direct alcohol metabolite.
- 100 ng/mL: sensitive to lower or older exposure
- 200 ng/mL: an intermediate threshold
- 500 ng/mL: more specific but less sensitive over time
What an EtG result can and cannot tell you
A result can support recent ethanol exposure. It generally cannot establish the exact number of drinks, the precise time of drinking, or whether someone was impaired. Clinical context, sample validity, medications, incidental exposure, and the testing method all matter.
EtG versus breath and blood alcohol
Breath and blood alcohol tests look for ethanol and are most useful close to the drinking event. Urine EtG looks for a metabolite, so its detection window is usually longer. That longer window makes EtG useful for monitoring abstinence, but also makes careful interpretation essential.
Frequently asked questions
Does a positive EtG test mean intoxication?+
No. EtG indicates ethanol exposure, not current impairment or blood alcohol concentration.
Can EtG identify how many drinks were consumed?+
Not reliably. Concentrations overlap across people and are affected by timing and urine dilution.
Evidence and limitations
This guide summarizes primary research and public-health guidance. Group-level findings cannot predict one person's result.