EtG test FAQ: detection times, cutoffs, and results

An EtG test detects ethyl glucuronide, a direct metabolite formed after the body processes ethanol. Urine EtG can remain measurable after alcohol is no longer detectable in breath or blood. It indicates ethanol exposure, not current intoxication.

EtG stands for ethyl glucuronide. It is produced when a small portion of ethanol is joined with glucuronic acid and then excreted, mainly in urine.

EtG testing is used in clinical monitoring, treatment programs, workplace or professional programs, and other situations where recent alcohol exposure is relevant. The meaning of a result depends on the program, cutoff, method, and collection context.

No. EtG can remain after ethanol has cleared, so it cannot establish current impairment or blood alcohol concentration. Breath or blood ethanol testing has a different purpose and shorter time frame.

No. Concentrations overlap widely across people and drinking events. A result can support recent exposure but generally cannot determine an exact hour, number of drinks, or drinking pattern.

Detection is often strongest in the first 24 hours, becomes more variable during 24–48 hours, and declines further after 48 hours. Heavy or repeated drinking and lower cutoffs can extend the window, but no timeline applies universally.

No. Eighty hours is a possible upper-end window after substantial exposure in some circumstances, not a guaranteed detection period. Dose, cutoff, urine concentration, and individual biology affect whether EtG remains above the reporting threshold.

Yes, a sensitive test may detect one drink for a period of time, particularly at a low cutoff and soon after exposure. The duration is typically shorter and less predictable than after heavier drinking.

Yes. Recent drinking is commonly detectable at 24 hours, although light exposure, a higher cutoff, and a dilute sample can reduce sensitivity.

It can be, especially after heavier or repeated drinking and at lower cutoffs. Sensitivity is lower than during the first day, so neither a positive nor negative outcome can be guaranteed.

Some exposures remain detectable at 72 hours, but this is an increasingly uncertain part of the window. It is more plausible after substantial exposure or with a lower reporting cutoff.

Timing is usually counted from the end of drinking because ethanol continues to be absorbed and metabolized during a drinking session. Studies and laboratories may define timing differently, so report details matter.

A 100 ng/mL cutoff reports relatively low EtG concentrations. It is more sensitive to light or older exposure but also raises more concern about incidental alcohol sources and low-level interpretation.

A 500 ng/mL cutoff is more specific and less likely to report some low-level incidental exposures. It also loses sensitivity sooner and may miss lighter or older drinking that a lower cutoff detects.

Yes. Two hundred ng/mL is used as an intermediate threshold in some testing settings. It balances greater sensitivity than 500 ng/mL with more specificity than 100 ng/mL.

Yes. A sample measuring 300 ng/mL is positive at 100 or 200 ng/mL but negative at 500 ng/mL. A result should always be interpreted using the laboratory's stated cutoff.

It means the measured concentration was below that test's reporting cutoff. It does not prove that no ethanol exposure occurred, particularly when the exposure was small, older, or the sample was dilute.

It means EtG was measured at or above the stated cutoff. The result supports ethanol exposure but should be interpreted with confirmation method, concentration, creatinine, EtS, timing, and relevant policy.

No. EtG concentration varies with time, urine production, renal function, dose, drinking pattern, and assay characteristics. Reverse-calculating an exact drink count is not reliable.

EtG and ethyl sulfate (EtS) are separate direct ethanol metabolites produced through different pathways. Their windows overlap, and testing both can provide corroborating context when a result is unexpected.

Creatinine helps indicate how concentrated or dilute a urine sample is. A low creatinine result may trigger a dilute-sample policy or make a low EtG concentration harder to interpret.

Water does not reliably accelerate the body's elimination of EtG. It can temporarily dilute urine, but laboratories may identify low creatinine or apply sample-validity rules.

Dilution can lower a measured concentration below a cutoff, but it can also make the sample reportable as dilute or unsuitable. Policies differ, and deliberate overhydration is not a dependable strategy.

Creatinine-normalized EtG adjusts the EtG concentration relative to urine creatinine to reduce some variation caused by sample concentration. It can add context but does not create an exact drinking timeline.

Microbial activity and poor storage can complicate some alcohol-marker results. Proper collection, refrigeration or preservation, timely analysis, and EtS comparison help reduce uncertainty.

Heavy or repeated exposure to alcohol-based sanitizer can create low-level interpretation concerns, especially with sensitive cutoffs. Routine use does not automatically explain every positive result; concentration and context matter.

Ethanol-containing mouthwash can expose a person to alcohol. It is more relevant to low-level results and lower cutoffs than to clearly high concentrations, but the actual report and testing policy should be reviewed.

Some fermented foods, flavorings, or products contain small amounts of ethanol. These sources can complicate low-level results but should not be assumed to explain a result without examining concentration, timing, and confirmation.

Some liquid medicines contain ethanol and may create genuine exposure rather than analytical interference. Keep product labels and discuss necessary medication with the testing program before collection when possible.

Request the numerical result, cutoff, confirmation method, creatinine, EtS result, and collection time. Document relevant products or medicines and discuss the report with the responsible laboratory, clinician, program, or attorney.

Home strips can provide a useful cutoff-based screen when stored and used correctly. They generally do not provide a confirmed quantitative result and should not decide medical, employment, supervision, or legal matters.

Laboratories can use controlled collection, sample-validity checks, numerical measurement, and specific confirmation methods such as mass spectrometry. These features provide more information than a single home test strip.

No. A calculator cannot measure your urine concentration, creatinine, renal function, assay performance, or all individual variation. EtG Calculator Pro shows an educational range and explicitly avoids pass/fail guarantees.

The most useful inputs are standard-drink count, the end of drinking, drinking-session length, repeated versus single-day exposure, and the actual laboratory cutoff. Even with these inputs, the result remains uncertain.

No. Calculator inputs are processed locally in the browser and are not submitted to create a profile or calculation history.

No. The calculator is educational and has not been clinically validated as a diagnostic device. Consequential decisions require the actual laboratory report and qualified professional interpretation.