Skip to content
Blood Test Tracker

Ethanol (Blood Alcohol)

Measures how much alcohol (ethanol) is in your blood at the moment of the draw. It is a snapshot of very recent drinking, not a long-term marker.

AI-verified against cited sources. Awaiting expert reviewAlso called EtOH, BAC, SACLOINC 5643-2

Check your result

Sex (optional)

Type your result to see where it falls.

Nothing you type here leaves your browser.

What it is

Ethanol is the alcohol in beer, wine and spirits. This test measures how much is in the liquid part of your blood (serum or plasma). The level rises as you drink and falls as your liver breaks the alcohol down, on average by about 15 mg/dL each hour. Without drinking, blood holds only a trace. Most labs report anything under about 10 mg/dL as 'not detected'.

Why it matters

Clinicians order this test in urgent care to help explain confusion, injury or drowsiness, and it is sometimes used for treatment, workplace or legal reasons. The same number can mean different things in different settings. Serum and plasma results run about 15% higher than whole blood, and legal driving limits (usually 0.08% in the US) are generally set for whole blood or breath, not serum.

If it’s high

A higher result means more alcohol was in your blood when it was drawn. How a given level affects a person varies a lot, and people who drink often may show fewer signs at the same number. Very high levels can slow breathing and lower alertness, which is why labs phone the ordering clinician when a result passes a set limit.

Common causes

  • Recent drinking of beer, wine or spirits
  • Drinking quickly or on an empty stomach, which tends to raise the peak level
  • Alcohol in some liquid medicines or other products that were swallowed

What can help

  • Ask your clinician how to read the number given how you feel and what you drank
  • Avoid driving or other risky tasks until the alcohol has cleared
  • If you are worried about your drinking, ask your clinician about support options

Usual ranges

What labs print as the reference range, by who was tested. Ranges differ a little between labs, so the range on your own report is the one your result is judged against.

For adults: up to 10 mg/dL. Source: Biochemia Medica, ARUP Laboratories. Labs treat above 250 mg/dL as urgent.

What can affect your result

  • How much you drank and how fast
  • Food in the stomach, body weight, age and sex
  • Medicines and the type of drink
  • Time since your last drink
  • Sample type: serum or plasma reads about 15% higher than whole blood, and some labs test whole blood instead
  • Alcohol swabs used at the draw site and tubes that were not sealed
  • Alcohol-based skin cleanser at the draw site can contaminate the sample, so labs ask for a non-alcohol cleanser.
  • An uncapped or poorly capped tube can lose alcohol, so labs ask that tubes be sealed tightly.
  • Serum or plasma reads about 15% higher than whole blood (range 10-20%), which matters when a result is compared with a legal limit written for whole blood.
  • Some enzymatic methods can read falsely high when lactate and lactate dehydrogenase are both very high.
  • Hemolysis (damaged red cells) can lower enzymatic results by roughly 6-16% in laboratory studies.

Any time. The result is a snapshot of the moment the blood was drawn. Once drinking stops, the level falls by about 15 mg/dL (0.15 g/L) per hour on average. The rate differs from person to person.

When to talk to a clinician

If you or someone with you is very drowsy, confused, can't be woken, vomits repeatedly or breathes slowly or irregularly after drinking, call 911 or your local emergency number. If a lab reports a result above its critical limit (ARUP's is 250 mg/dL), the ordering clinician is usually called right away.

Questions you could ask

  • What was this test ordered to check, and how will the result be used?
  • Is this serum result being compared with a whole-blood legal limit?
  • What does this level mean for me given how much I drank and how I feel?
  • Would it help to talk about my alcohol use or about support options?

Questions people ask

Is this the same as the blood alcohol number used for driving limits?

Not exactly. Driving limits are generally set for whole blood or breath, and the legal limit in the US is usually 0.08% (80 mg/dL). Serum or plasma results are about 15% higher than whole blood, so a lab or legal expert has to convert before comparing.

How do I convert between mg/dL, g/dL, % and mmol/L?

80 mg/dL is the same as 0.08 g/dL, 0.08% (weight per volume) and 0.8 g/L. To get mmol/L, multiply mg/dL by 0.2171, so 80 mg/dL is about 17.4 mmol/L.

How long can alcohol be found in the blood?

MedlinePlus says a blood test can detect alcohol for up to about 12 hours after the last drink. The exact time depends on how much you drank and how quickly your body clears it.

Show the science and sources

Units

  • 1 mg/dL = 1 mg/dL
  • 1 mg/dL = 0.001 g/dL
  • 1 mg/dL = 0.01 g/L
  • 1 mg/dL = 0.2171 mmol/L

Open the Blood Alcohol unit converter

For clinicians and researchers

Hospital labs usually measure ethanol in serum or plasma by an enzymatic alcohol dehydrogenase (ADH) assay with NADH detection. ARUP uses gas chromatography. Studies put the detection limit near 5 mg/dL and the quantitation limit at 10-20 mg/dL. Serum or plasma ethanol is about 15% higher than whole blood (range 10-20%), and mass/mass (g/kg) forensic units come out slightly lower than mass/volume because blood density is 1.055 g/mL and serum 1.030 g/mL. Endogenous ethanol in healthy people is about 0.001 g/L, so no real reference range exists. Lactate plus lactate dehydrogenase can cause false positives with ADH reagents. Acetone and ketones do not interfere, and isopropanol interference is mostly an issue with older assays. Free hemoglobin biases results low by about 6-16%. Average ethanol oxidation is about 0.15 g/L per hour. Statutory driving limits are mostly 0.5 g/L (50 mg/dL) worldwide, with a range of 0.2-0.8 g/L, and the US limit is usually 0.08% (0.08 g/dL, per MedlinePlus). ADH assays are not a substitute for gas chromatography in forensic work.

LOINC 5643-2 (primary), 14336-2, 14719-9, 5640-8. Specimen: serum-or-plasma.

Sources

  1. The enzymatic analysis of alcohol (ethanol) in serum and plasma with the alcohol dehydrogenase reagent: focus on intra-analytical and post-analytical aspects, Biochemia Medica (2025)
  2. Ethanol, Serum or Plasma - Medical (test 0090120), ARUP Laboratories
  3. ARUP Critical Values List (CORP-APPEND-0104A, Rev. 46, April 2026), ARUP Laboratories (2026)
  4. Blood Alcohol Level, MedlinePlus (National Library of Medicine)
  5. Ethanol (PubChem CID 702), PubChem (National Library of Medicine)

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

Related markers