The EtS Field Guide
A source-backed calculator for urine alcohol testing, recent alcohol use, and ethyl sulfate detection windows.
Urinary EtS over time
① The curve is a paired alcohol-metabolite model, not a lab result. BAC is overlaid with a fixed visual scale, and the EtG context line uses the same ng/mL axis.
Detection thresholds, and who uses them
A "positive" EtS depends on where somebody drew the line. EtS cutoffs are less standardized than EtG, so the program's written rule matters.
EtS is usually most useful as a paired alcohol marker. If paperwork says "UA" or "urine drug screen," that does not prove EtS was ordered; alcohol biomarkers are separate orders unless the program adds them.
What the curve is actually telling you
EtS is a metabolite, not alcohol.
EtS, short for ethyl sulfate, is a direct ethanol metabolite. Many urine alcohol panels measure EtS alongside EtG because both can remain detectable after ethanol itself is gone.
Controlled-drinking studies show EtG and EtS extending the urine detection window beyond urine ethanol itself3. EtS is not a replacement for EtG so much as a second direct marker that can help interpretation.
EtS is usually paired with EtG.
The research literature usually studies EtG and EtS together. After a medium ethanol dose, urinary EtS peaked lower and a little earlier on average than EtG, but people varied widely2.
During detoxification, EtG and EtS both remained detectable for several days, again with wide person-to-person variation4. That is why this page treats the curve as a paired-marker approximation rather than an individual prediction.
Low cutoffs are sensitive, not universal.
EtS cutoff standards are less settled than EtG. One cutoff investigation treated 50-100 ng/mL EtS as sensitive territory and explicitly called for more research before treating low EtS cutoffs as settled rules5.
Incidental exposure still matters. Intensive high-ethanol mouthwash use produced low EtS values in some subjects, while 500 ng/mL remained conservative in that study6.
Why this isn't a test result
Real labs integrate over variable urine volumes, specimen timing, cutoffs, and confirmation methods. The graph above is the shape of a paired EtS model, not the number a cup in a bathroom will produce on a Tuesday morning. Treat it as a teacher, not a witness.
Urine concentration changes the number.
The test measures concentration (ng/mL) of EtS, not the total amount your body has produced. Urine volume and timing can therefore move the measured number around even when the underlying metabolism is unchanged.
Labs know this. Many programs check creatinine, specific gravity, and other validity markers so a diluted specimen can be reported as dilute or invalid rather than simply negative.
That is why the graph is best read as a concentration model with uncertainty around any real sample, not a guarantee about how a lab will classify one cup of urine.
How the model works
The calculator is intentionally small: a cited set of assumptions feeds one pharmacokinetic model, and the chart renders that result. These are the assumptions currently active in the curve above.