Key calculations

Heuristic Reference Range

The calculator uses a transparent heuristic reference model based on drink count, selected cutoff, and drinking-pattern adjustments. It is not a validated pharmacokinetic model and does not estimate the EtG concentration in a urine specimen.

Pattern Adjustment

The pattern setting is a coarse scenario adjustment, not a measurement of absorption or metabolism. It can move the reference range, but it cannot represent the timing, dose, physiology, or laboratory variability of a specific person.

Cutoff Scaling

A higher cutoff generally detects only higher reported concentrations, while a lower cutoff is more analytically sensitive. The calculator interpolates between hand-set anchors; those anchors are not universal laboratory reference ratios and should not be treated as validated detection probabilities.

Elapsed-Time Position

Elapsed hours are compared with the model range and labeled before, within, or beyond it. Being beyond the range does not mean a specimen must be negative, and being within it does not mean a specimen must be positive.

Reference ranges

Single Session (1–3 drinks)

A low-volume single session may produce a shorter model range than larger or prolonged intake, but no fixed range applies to every person. Use the output only as an educational comparison, not as a test prediction.

Extended Window (3–6 drinks)

Drinking spread over several hours can change the timing of peak and elimination, but the direction and size of the effect vary. The model's pattern adjustment is deliberately coarse and not clinically validated.

Heavy Binge (6+ drinks)

Higher-volume sessions generally warrant greater caution, but the calculator cannot convert drink count into an individual EtG concentration or guaranteed detection duration. A laboratory result remains the only way to assess a specimen.

Cutoff Sensitivity

Cutoff values change analytical sensitivity and reporting context. A lower cutoff may detect lower concentrations, but cutoff alone does not determine an individual's result; specimen dilution, assay method, EtG/EtS testing, and policy also matter.

How to use it

1. 1.Select your drinking patternChoose Single Session for drinks consumed within 1–2 hours, Extended Window for drinks spread across many hours, or High-Intensity for sustained high-volume sessions. The pattern adjusts the peak EtG concentration and elimination curve.
2. 2.Enter the number of drinksEnter the total number of standard drinks consumed (12 oz beer, 5 oz wine, or 1.5 oz spirits = 1 standard drink). Be as accurate as possible — this is a primary driver of the detection window.
3. 3.Enter time since last drinkInput the number of hours that have passed since you finished your last drink. This is subtracted from the raw estimate to determine the remaining detection window.
4. 4.Choose your test cutoffSelect 100, 250, or 500 ng/mL to match your test, or choose Custom to enter a value between 50 and 1000 ng/mL in steps of 50. Confirm the cutoff and reporting policy with the laboratory or program that ordered the test.
5. 5.Review the detection windowRead the earlier and later reference points as model boundaries, then note whether the elapsed time is before, within, or beyond that range. The preset comparison cards show how cutoff assumptions change the heuristic range; they do not predict a pass or fail result.
6. 6.Interpret the model positionThe position label only describes where elapsed time falls relative to this model's reference range. It is not a risk score and does not indicate a laboratory result.