EtG Cutoff Calculator: 100 vs 500 ng/mL Comparison
Different programs use different EtG cutoffs. This calculator shows your estimated level against both 100 ng/mL and 500 ng/mL so you can understand the gray zone and why one threshold may be stricter than another.
Editorial note
This educational page is maintained by EtGCalc and reviewed against published EtG research, SAMHSA guidance, and our calculator methodology. It does not provide medical or legal advice.
Enter Your Details
How to Use This Calculator
Enter your sex, weight, drink count, drink type, and time since your last drink. The calculator estimates your EtG level and compares it with common 100 ng/mL and 500 ng/mL cutoffs. For a broader explanation, read our EtG calculation guide.
1100 vs 500 ng/mL: What Is the Difference?
A 500 ng/mL cutoff is commonly used to reduce the chance that low-level incidental exposure is treated as drinking. A 100 ng/mL cutoff is more sensitive and may be used in stricter monitoring settings.
The calculator compares both thresholds because the same estimated level can be negative at 500 ng/mL but positive at 100 ng/mL.
- 100 ng/mL: more sensitive, longer window
- 500 ng/mL: standard cutoff in many settings
- 100-500 ng/mL: gray-zone range
2The Gray Zone Explained
The gray zone usually refers to EtG levels between 100 and 500 ng/mL. This range can be interpreted differently depending on program rules, timing, EtS confirmation, and exposure context.
If your estimate falls in this range, the exact cutoff matters more than broad statements about pass or fail.
Gray-zone result
A level of 250 ng/mL is negative at 500 ng/mL but positive at 100 ng/mL.
3Which Cutoff Does Your Test Use?
Ask the testing program or review the lab paperwork if you can. Courts, probation offices, clinical programs, and workplaces may use different thresholds.
When you do not know the cutoff, compare both and plan around the stricter one.
- Probation and treatment programs may use stricter thresholds
- Workplace or forensic tests may use 500 ng/mL
- Lab reports usually list the cutoff near the result
Cutoff Interpretation Table
| Scenario | Estimate | Context |
|---|---|---|
| 75 ng/mL | Negative | Below both cutoffs |
| 250 ng/mL | Gray zone | Positive at 100, negative at 500 |
| 750 ng/mL | Positive | Above both common cutoffs |
| 1,500 ng/mL | High positive | Strong recent-use signal |
Frequently Asked Questions
Is 100 ng/mL stricter than 500 ng/mL?
Yes. The 100 ng/mL cutoff detects lower levels and usually creates a longer detection window.
What is the EtG gray zone?
The gray zone is commonly the 100-500 ng/mL range, where interpretation depends on cutoff and context.
Can I pass at 500 but fail at 100?
Yes. Any estimated level between 100 and 500 ng/mL is negative at 500 but positive at 100.
Which cutoff should I choose?
Use the cutoff listed by your testing program. If unknown, compare both and treat 100 ng/mL as the stricter scenario.
Does EtS help with cutoff disputes?
EtS can provide additional context because it is less prone to some incidental or sample-related issues.
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Medical & Legal Disclaimer
Not Medical Advice
EtGCalc does not provide diagnosis, treatment, or medical advice. Talk with a qualified healthcare provider about alcohol use, metabolism, testing concerns, or recovery.
Not Legal Advice
EtG testing can affect probation, custody, licensing, and employment decisions. Consult a licensed attorney or your testing program for legal questions.
If You Need Support
In the United States, SAMHSA's National Helpline is 1-800-662-4357. It is free, confidential, and available 24/7.
Calculator output is an estimate, not a test prediction. Individual metabolism, hydration, kidney function, genetics, specimen handling, and lab cutoff policy can change real results. See our methodology and sources.
References
- 1SAMHSA. The Role of Biomarkers in the Treatment of Alcohol Use Disorders, 2012 Revision.
Used for biomarker context, cutoff interpretation, and incidental exposure cautions.
- 2Jatlow et al. Ethyl glucuronide and ethyl sulfate assays in clinical trials, 2014.
Used for urinary EtG and EtS kinetics after alcohol exposure.
- 3McDonell et al. Using ethyl glucuronide in urine to detect alcohol use, 2015.
Used for EtG detection window context in clinical monitoring populations.
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