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Acetaldehyde Blood Test: Measuring a Key Byproduct of Alcohol Metabolism

Published: August 9, 2026Updated: August 10, 2026

This test detects the presence of acetaldehyde, a toxic byproduct of alcohol metabolism, in your blood to help evaluate how your body processes alcohol.

Quick summary

{"Acetaldehyde is a harmful substance produced when your liver breaks down alcohol","This test checks if acetaldehyde is present in your blood serum or plasma","It helps identify people who have difficulty metabolizing alcohol due to enzyme deficiencies","The presence of acetaldehyde may indicate recent alcohol consumption or impaired alcohol processing"}

Medically reviewed by WellAlly Editorial TeamLast reviewed August 10, 2026Editorial policy

Key facts at a glance

LOINC
35118-9
Short code
ACET
Synonyms
Acetaldehyde SerPl Ql
Category
chemistry
Sample
serum
Container
Serum separator tube (SST) or Sodium fluoride/potassium oxalate gray-top plasma tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
≥ 18 years
Method
Enzymatic assay or Headspace gas chromatography with flame ionization detection (HS-GC-FID)
CPT
82046
SNOMED
271949004
Specimen volume
2-5 mL
Stability
Store at 2-8°C if analysis within 7 days; for longer storage, freeze at -20°C or below. Protect from light as acetaldehyde is volatile.
Hemolysis max
50
Lipemia max
100
Icterus max
20
TAT
24–72 hours
Order
routine

What is an acetaldehyde test, and what can the results tell me about how my body breaks down alcohol?

The acetaldehyde test is a laboratory test that detects whether acetaldehyde is present in your blood serum or plasma. Acetaldehyde is a toxic chemical compound that your body produces when it breaks down (metabolizes) alcohol (ethanol). This test does not measure the exact amount of acetaldehyde but simply determines if it is present or absent in your blood.

How is the acetaldehyde test performed, and what should I expect during the blood collection process?

A healthcare professional will collect a blood sample from a vein in your arm using a small needle. The blood is then placed in a special tube and sent to a laboratory for analysis. The test looks for the presence (or absence) of acetaldehyde in the liquid part of your blood (serum or plasma).

Why is acetaldehyde important to my health, and how does it affect symptoms like flushing, nausea, and hangover?

Acetaldehyde is produced when alcohol dehydrogenase (ADH) enzymes in your liver convert ethanol into acetaldehyde. Then, another enzyme called aldehyde dehydrogenase (ALDH) normally converts acetaldehyde into harmless acetate. However, some people have a genetic variation that makes their ALDH enzyme less effective, leading to acetaldehyde buildup. This buildup can cause unpleasant symptoms like facial flushing, rapid heartbeat, and nausea after drinking alcohol.

Reference range

Not detected (Negative)N/A

Specimen: serum

Patient should avoid alcohol consumption for at least 24 hours prior to specimen collection. Inform laboratory of any medications or recent exposure to industrial chemicals. No other special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Detecting acetaldehyde presence is clinically important for several reasons. First, it can indicate recent alcohol consumption since acetaldehyde is produced during alcohol metabolism. Second, it helps identify individuals with aldehyde dehydrogenase (ALDH2) deficiency, commonly known as alcohol flush reaction, which is more prevalent in people of East Asian descent. Third, it may be used to assess liver function and the body's ability to process toxins. Finally, in research settings, it may be used to study alcohol metabolism and related metabolic disorders.

Frequently asked questions

Do I need to fast before this test?
Typically, you do not need to fast before an acetaldehyde test. However, you should inform your healthcare provider about any recent alcohol consumption, as this may affect the results. It is also important to tell them about any medications or supplements you are taking.
What does a positive result mean?
A positive result means acetaldehyde was detected in your blood, which typically indicates recent alcohol consumption or that your body is having difficulty metabolizing alcohol. The presence of acetaldehyde can occur even after small amounts of alcohol in people with ALDH2 enzyme deficiencies.
What does a negative result mean?
A negative result means no acetaldehyde was detected in your blood sample. This could mean you have not consumed alcohol recently, or your body is efficiently metabolizing any acetaldehyde produced. However, timing is important as acetaldehyde is typically cleared from the blood within a few hours after alcohol consumption.
Is this test used to diagnose alcoholism?
This test is not typically used as a primary diagnostic tool for alcoholism. Other tests and assessments are more commonly used for alcohol use disorder diagnosis. However, detecting acetaldehyde can provide information about recent alcohol consumption and metabolism patterns.
  1. 1
    MedlinePlus - Alcohol MetabolismSource
  2. 2
    Mayo Clinic - Liver Blood TestsSource
  3. 3
    National Institute on Alcohol Abuse and AlcoholismSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 10, 2026. · Read our editorial policy