PEth Test Chart (ng/mL Levels Explained)
Understanding your PEth test results can feel confusing. This PEth test chart explains what different PEth levels (20, 50, 80, 200 ng/mL and higher) mean and how laboratories interpret blood alcohol biomarkers.
Phosphatidylethanol (PEth) is a direct biomarker of alcohol consumption formed in red blood cells. Unlike ETG urine testing, PEth reflects alcohol intake over the past 2–4 weeks.
How to Read a PEth Test Chart
A PEth test chart organizes blood alcohol biomarker levels into ng/mL ranges. These ranges help laboratories determine whether alcohol use was light, moderate, or heavy within the past 2–4 weeks.
📊 PEth Test Results Chart
| PEth Level (ng/mL) | Result Interpretation | Drinking Pattern | Clinical Meaning |
|---|---|---|---|
| < 20 ng/mL | Negative | No or very light drinking | Consistent with abstinence |
| 20 ng/mL | Low Positive | Light drinking | Early alcohol exposure |
| 50 ng/mL | Moderate | Repeated drinking | Regular alcohol intake |
| 80 ng/mL | Significant | Heavy drinking pattern | Strong evidence of use |
| 200 ng/mL | Very High | Chronic heavy drinking | Sustained alcohol consumption |
| 400+ ng/mL | Extremely High | Severe heavy drinking | Possible alcohol use disorder |
What Does 20 ng/mL Mean?
A PEth level of 20 ng/mL is often used as the lowest cutoff for a positive PEth test. It may indicate light drinking within the past 2–4 weeks. Some laboratories consider values below 20 ng/mL consistent with abstinence.
What Does 50 ng/mL Indicate?
A 50 ng/mL PEth level typically reflects repeated alcohol use. This level suggests more than occasional drinking and may indicate moderate consumption patterns.
Is 80 ng/mL Considered Heavy Drinking?
Yes. Many clinical guidelines consider 80 ng/mL a marker of significant or heavy drinking. At this level, alcohol consumption has likely occurred consistently over several weeks.
What Does 200 ng/mL or Higher Mean?
A PEth level of 200 ng/mL or above strongly suggests chronic heavy alcohol consumption. Higher values (400+ ng/mL) are often associated with sustained heavy drinking patterns.
How Long Does PEth Stay Detectable?
PEth can remain detectable in blood for approximately 2 to 4 weeks after alcohol consumption. Detection time varies depending on:
- Amount of alcohol consumed
- Frequency of drinking
- Body weight and gender
- Metabolism and liver function
PEth Cutoff Levels Used by Laboratories
Different laboratories may use different cutoff levels. Common thresholds include:
- 20 ng/mL – Light drinking detection
- 50 ng/mL – Moderate drinking threshold
- 80 ng/mL – Heavy drinking marker
Always confirm your results with the testing laboratory for official interpretation.
PEth vs ETG: What’s the Difference?
- PEth → Detects long-term alcohol use (2–4 weeks, blood test)
- ETG → Detects short-term alcohol use (up to 3–5 days, urine test)
To estimate your expected blood results, use our PEth Level Calculator for a personalized calculation.
For short-term urine detection, try our ETG Calculator.
Important Disclaimer
This PEth test chart is for educational purposes only. Individual metabolism varies, and laboratory confirmation is required for medical, legal, or probation decisions.