Looking at your ETG test results can be confusing—especially when numbers like "847 ng/mL" don't mean anything to you.
This guide breaks down exactly what those numbers mean and whether you should be concerned.
- ng/mL = nanograms per milliliter. It measures how much ETG is in your urine.
- Your result is compared to a 'cutoff'—typically 500 or 100 ng/mL.
- Below the cutoff = Negative. Above = Positive.
- Higher numbers mean more recent or heavier drinking.
Quick Reference: ETG Level Interpretation
Here's what different ETG levels typically mean:
| Level (ng/mL) | Result | What It Usually Means |
|---|---|---|
| < 100 | Negative | Typically no detectable alcohol use in ~80 hours |
| 100-499 | Depends* | Negative at 500 cutoff, Positive at 100 cutoff |
| 500-999 | Positive | Light-moderate drinking in past 24-48 hours |
| 1,000-9,999 | Positive | Moderate-heavy drinking in past 24-72 hours |
| ≥ 10,000 | High Positive | Heavy/binge drinking, likely within 24 hours |
*Whether 100-499 ng/mL is a "pass" depends on which cutoff your test uses.
Want to estimate your level? Use our ETG Calculator to get a personalized estimate based on your drinking.
Understanding ng/mL Levels in ETG Tests
ng/mL stands for "nanograms per milliliter"—a standard unit for measuring tiny amounts of substances in fluids.
How Small Is a Nanogram?
Think of it this way:
- A gram is about the weight of a paperclip
- A milligram is 1/1,000 of a gram (tiny grain of salt)
- A nanogram is 1/1,000,000 of a milligram
ETG is present in such small amounts that we need these ultra-precise units to measure it.
Why This Unit?
Your body converts alcohol into ETG, but only a tiny fraction ends up in urine. Even after heavy drinking, ETG levels are measured in the thousands of ng/mL—still incredibly small amounts by everyday standards.
Positive vs. Negative: How It's Determined
Your test result isn't just a number—it's compared to a "cutoff" threshold.
How Cutoffs Work
Your ETG Level < Cutoff = NEGATIVE (Pass)
Your ETG Level ≥ Cutoff = POSITIVE (Fail)
Common Cutoff Levels
| Cutoff | Typical Use | Sensitivity |
|---|---|---|
| 500 ng/mL | Employment, DOT testing | Standard—fewer false positives |
| 300 ng/mL | Some workplace programs | Moderate |
| 100 ng/mL | Probation, court, intensive monitoring | Very strict—longer detection |
Same Level, Different Results
Here's why the cutoff matters:
Example: Your result is 350 ng/mL
- At 500 ng/mL cutoff: ✅ NEGATIVE (you pass)
- At 100 ng/mL cutoff: ❌ POSITIVE (you fail)
If you don't know your cutoff, assume 100 ng/mL to be safe. For more details, see our ETG Test Cutoff Levels guide.
Understanding Your Report
Most ETG test reports include several pieces of information. Here's what they mean:
Key Fields on Your Report
| Field | What It Means |
|---|---|
| Specimen ID | Unique identifier for your sample |
| Collection Date/Time | When your urine was collected |
| EtG Result | Your level in ng/mL (or just "Positive/Negative") |
| Cutoff | The threshold used (e.g., 500 ng/mL) |
| Final Result | POSITIVE or NEGATIVE |
| Confirmation Method | Usually "LC-MS/MS" for confirmed results |
Screening vs. Confirmation
Many programs use a two-step process:
- Initial Screen (Immunoassay) — Fast, less expensive, may show "presumptive positive"
- Confirmation (LC-MS/MS) — More accurate, used to verify positive screens
If your report says "presumptive positive," wait for confirmation before panicking.
What Your Level Says About Drinking
Higher ETG levels generally indicate more recent or heavier drinking.
Interpreting Different Ranges
Very High (10,000+ ng/mL)
- Heavy or binge drinking
- Likely within the last 24 hours
- Multiple drinks consumed
High (1,000-10,000 ng/mL)
- Moderate to heavy drinking
- Usually within 24-48 hours
- Could be 3-6+ drinks
Moderate (500-1,000 ng/mL)
- Light to moderate drinking
- Possibly 48-72 hours ago
- Or lighter recent drinking
Low Positive (100-500 ng/mL)
- Light drinking several days ago
- OR heavier drinking 2-3+ days ago
- Levels are clearing but still detectable
Negative (< 100 ng/mL)
- No detected drinking in detection window
- OR drinking was long enough ago to clear
Important Caveat
These are general patterns. Individual metabolism varies significantly. Someone with faster metabolism might show 500 ng/mL where another person would show 1,000 ng/mL after the same drinking.
What About Creatinine Levels?
Some reports include creatinine testing. Here's why:
Why Test Creatinine?
Creatinine is a natural waste product in urine. Testing it helps detect:
- Dilute samples — Too much water before the test
- Substituted samples — Not human urine
Normal Creatinine Range
| Level | Interpretation |
|---|---|
| ≥ 20 mg/dL | Normal—sample is valid |
| 2-20 mg/dL | Dilute—may require retest |
| < 2 mg/dL | Substituted—likely not human urine |
What "Dilute" Means for You
A "dilute negative" means your creatinine was low but ETG was below cutoff. Different programs handle this differently:
- Some accept it as a negative
- Others require a retest
- Some count it as a presumptive positive
If you get a dilute result, ask your program coordinator how they handle it.
Understanding Flagged Results
Your report might show special flags beyond just positive/negative:
| Flag | What It Means | What Happens |
|---|---|---|
| Dilute Negative | Low creatinine, no ETG detected | May need retest |
| Dilute Positive | Low creatinine, but ETG still positive | Usually counts as positive |
| Adulterated | Something was added to the sample | Typically counts as refusal |
| Substituted | Sample doesn't appear to be human urine | Typically counts as refusal |
| Invalid | Sample couldn't be analyzed | Requires new collection |
What to Do After Getting Your Results
If Your Result Is Negative
- No action typically needed
- Keep a copy of your report for records
- Continue following your program requirements
If Your Result Is Positive
- Stay calm — Panicking won't help
- Review the details — Check the cutoff, your level, and date
- Consider the timeline — Does this match your drinking history?
- Think about false positives — Did you use any products containing alcohol?
- Know your options — You may be able to request confirmation testing
If You Believe It's Wrong
- Document any potential exposure sources (hand sanitizer, mouthwash, medications)
- Request EtS (ethyl sulfate) testing if available—it's less affected by incidental exposure
- Consult with a lawyer for legal testing situations
- See our ETG False Positive guide for more information
Related Resources
- ETG Calculator — Estimate your current level
- ETG Test Cutoff Levels — Deep dive into thresholds
- ETG False Positive Guide — Incidental exposure concerns
- Factors Affecting ETG — What influences detection time
- Realistic ETG Detection Times — Expected detection windows
A 'normal' or negative result means your EtG level is below the test cutoff—typically less than 500 ng/mL for standard tests or less than 100 ng/mL for strict monitoring. There's no 'normal' baseline level; non-drinkers should have undetectable EtG.
500 ng/mL is moderate. It's right at the standard cutoff threshold, indicating possible light drinking within 24-48 hours or moderate drinking 48-72 hours prior. For a 500 ng/mL cutoff test, this would be borderline. For a 100 ng/mL cutoff, this is clearly positive.
A 'negative dilute' result means your urine showed no EtG above the cutoff, but the creatinine level was low—suggesting the sample was diluted (either intentionally or from over-hydration). Some programs accept this as negative; others require a retest.
Yes. While some reports only show 'positive' or 'negative,' you can typically request the quantitative result (exact ng/mL). This is especially useful for understanding whether you were just above the cutoff or significantly over it.
At 500 ng/mL cutoff: typically 24-48 hours after moderate drinking. At 100 ng/mL cutoff: up to 80 hours after heavy drinking. Use our ETG calculator for a personalized estimate based on your consumption.
A presumptive positive is an initial screening result that indicates possible alcohol use. It should be confirmed by a more accurate method (LC-MS/MS). Don't panic—wait for the confirmation test before assuming the result is final.
Technically yes, but barely. Lab testing has inherent variability (±10-20%), so a result this close to the cutoff is risky. If you tested at 499 ng/mL, you could easily have been at 510 ng/mL with slightly different hydration. Don't cut it this close—aim to be well below your cutoff.
This page is for educational purposes only. It does not constitute medical or legal advice. Test result interpretation should be discussed with your healthcare provider, testing program coordinator, or legal counsel for guidance specific to your situation.