What This Chart Shows
This chart plots the project's ETG decay model against common 500 ng/mL and 100 ng/mL cutoff lines. It is a visual comparison tool, not the site's general detection-window guide:
| Scenario | Below 500 ng/mL | Below 100 ng/mL |
|---|---|---|
| 2 drinks (light) | ~13 hours | ~20 hours |
| 4 drinks (moderate) | ~16 hours | ~23 hours |
| 8 drinks (heavy) | ~19 hours | ~26 hours |
| 12 drinks (binge) | ~21 hours | ~28 hours |
Estimates use the project's 3-hour half-life model with 5,000 ng/mL peak per standard drink. Individual metabolism, hydration, and body composition can shift results, so read the curve as educational context rather than a lab-result guarantee.
How to Read the ETG Detection Time Chart
Page role: This page explains how to read the ETG chart's axes, colors, cutoff lines, and uncertainty. It is not the interactive chart tool or the general detection-times guide.
The ETG Detection Time Chart can be confusing at first glance. Use this guide to understand what the chart is showing before you rely on any single number.
- The chart shows estimated ETG levels decreasing over time
- Colors indicate relationship to the selected cutoff: below, near, or above
- Two lines show different cutoff thresholds (500 ng/mL vs 100 ng/mL)
- Your position on the chart depends on how much you drank and when
Now let's break down what the chart actually shows.
Understanding the Axes
The X-Axis: Time Since Last Drink
The horizontal axis shows hours elapsed since your last alcoholic drink. This is the most critical variable in ETG detection.
Key points:
- Time starts from when you stopped drinking, not when you started
- ETG levels peak 4-6 hours after your last drink
- The chart typically spans 0-80+ hours
The Y-Axis: ETG Concentration
The vertical axis shows ETG concentration measured in nanograms per milliliter (ng/mL). This is what the lab measures in your urine sample.
Understanding the scale:
- After drinking, ETG can spike to 10,000-50,000+ ng/mL
- The chart often uses a logarithmic scale (each step is 10× the previous)
- What matters is whether you're above or below the cutoff line
For the math behind these numbers, see our ETG calculation formula guide.
What the Colors Mean
The chart uses color coding to quickly show your detection risk level:
Below Cutoff
Below CutoffETG levels are below the testing threshold. Detection is unlikely on standard tests.
Example: The estimate is below the selected cutoff, but lab interpretation still depends on the program.
Uncertain
Near CutoffETG levels are in the borderline zone. The same estimate can sit below 500 ng/mL and above 100 ng/mL.
Example: Interpretation varies by test sensitivity and individual factors.
Above Cutoff
Above CutoffETG levels are significantly elevated. Detection is very likely on any standard test.
Example: High probability of positive result on most tests.
Important: These zones are estimates. Individual variation means your actual risk may differ by 20-30% from what the chart shows.
The Two Lines Explained
Most ETG charts show two horizontal lines representing different test sensitivities. Understanding which applies to you is crucial.
Quick Comparison: 500 vs 100 ng/mL
| Cutoff | Who Uses It | Detection Window | Risk Level |
|---|---|---|---|
| 500 ng/mL | DOT tests, most employers | 24-60 hours | More forgiving |
| 100 ng/mL | Probation, court orders, treatment programs | 48-80+ hours | Very strict |
The 500 ng/mL Line (Standard)
This is the standard cutoff used by most testing programs:
- Used for: Department of Transportation (DOT) tests, most employment screenings
- Detection window: Generally shorter (24-60 hours depending on consumption)
- More forgiving: You'll drop below this threshold faster
If your test uses a 500 ng/mL cutoff, focus on being below this line.
The 100 ng/mL Line (Strict)
This is the strict cutoff used for intensive monitoring:
- Used for: Probation, court-ordered testing, some treatment programs
- Detection window: Longer (48-80+ hours depending on consumption)
- More sensitive: Even small amounts of alcohol can be detected longer
If you're on probation or court-ordered monitoring, confirm the exact cutoff with your written order, testing administrator, or lab. Learn more about ETG test cutoff levels.
How to Use the Chart for Your Situation
Follow these steps to interpret the chart:
- Know Your Drinking Amount — Count your standard drinks accurately:
- 1 beer (12 oz, 5% ABV) = 1 standard drink
- 1 glass of wine (5 oz, 12% ABV) = 1 standard drink
- 1 shot (1.5 oz, 40% ABV) = 1 standard drink
- Find Your Time Point — Calculate hours since your last drink. Be precise—hours matter significantly.
- Locate Your Position — Find where your drinking amount and elapsed time intersect on the chart. Note which color zone you're in.
- Check Your Cutoff — Determine which line applies to your test (500 ng/mL or 100 ng/mL) and see if you're above or below it.
Want a personalized calculation? Try our full ETG Calculator for detailed results.
Common Mistakes When Reading the Chart
Mistake 1: Assuming the Chart is Exact
The chart shows averages. Your actual ETG levels could be 20-30% higher or lower due to:
- Individual metabolism differences
- Liver health and function
- Hydration levels
- Body composition
Better interpretation: Treat near-threshold estimates as uncertain, not as a guarantee. Lab method, urine concentration, and individual metabolism can all shift the final report.
Mistake 2: Using the Wrong Cutoff
Many people assume all tests use 500 ng/mL. Court-ordered and probation tests often use 100 ng/mL—a 5× more sensitive threshold.
Better interpretation: Ask your testing administrator about your specific cutoff level before making assumptions.
Mistake 3: Forgetting Peak Delay
ETG doesn't peak immediately. Levels continue rising for 4-6 hours after your last drink, then begin declining.
Solution: Count from when you stopped drinking, and remember the first few hours show increasing—not decreasing—levels.
Mistake 4: Ignoring the Confidence Interval
Being "just below" the line does not guarantee a negative lab report. There's inherent variation in both your metabolism and the test itself.
Better interpretation: A near-cutoff estimate should be discussed with the testing program or a qualified professional if the result has legal, employment, or medical consequences.
Factors That Shift Your Position
Several factors can move your actual levels higher or lower than the chart predicts:
Factors that may extend detection time:
- Slower metabolism (older age, liver issues)
- Higher body fat percentage
- Chronic heavy drinking (enzyme changes)
- Dehydration at test time
Factors that may shorten detection time:
- Faster metabolism (younger, healthier liver)
- Higher muscle mass
- Proper hydration
For detailed information, see our guide on factors affecting ETG levels.
When to Trust the Chart (and When Not To)
The chart is useful for:
- General planning and risk awareness
- Understanding how consumption amount affects detection
- Comparing relative risk between scenarios
The chart should NOT be used to:
- Make guarantees about test results
- Justify drinking close to test dates
- Replace professional advice in legal situations
Related Resources
- ETG Detection Time Chart — Interactive chart tool for plotting the model curve
- ETG Calculator — Personalized detection estimates
- ETG Test Cutoff Levels — Understanding thresholds
- ETG Calculation Formula — The math behind the estimates
The two lines represent different cutoff thresholds used by various testing programs. The 500 ng/mL line is the standard cutoff for employment and DOT tests. The 100 ng/mL line is the stricter cutoff used for probation, court-ordered, and some treatment program tests. Which line applies depends on your specific testing situation.
No. The chart shows population averages based on clinical studies. Individual variation is significant—your actual ETG levels could be 20-30% higher or lower than predicted. Factors like metabolism, liver health, body composition, urine concentration, and hydration all affect results.
If you're between the 500 ng/mL and 100 ng/mL lines, the same estimate is below a 500 ng/mL cutoff but above a 100 ng/mL cutoff. This is the 'uncertain' zone where interpretation depends on your specific cutoff, lab method, and individual variation.
The chart is most useful as an educational comparison tool. It helps explain how different drinking amounts can affect detection windows, but it should not be used as a guarantee or as timing advice for testing.
No. The chart shows averages with significant individual variation and should not be used as a guarantee. If you have regular testing obligations, the most reliable approach is complete abstinence. If you need support, visit our Get Help page for resources.
This page is for educational purposes only. It does not constitute medical or legal advice. Individual results vary significantly. The chart provides estimates based on population averages and should not be used as a guarantee of test results. Consult a healthcare provider or legal professional for guidance specific to your situation.