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Ethanol Test

Last updated March 31, 2018

Approved by: Krish Tangella MD, MBA, FCAP

Ethanol Testing is done to detect the presence and levels of alcohol in the body. The testing may be performed on blood, urine, saliva samples, or a sample of breath. It is also known as an Alcohol Test.

What are the other Names for this Test? (Equivalent Terms)

  • Alcohol Test
  • Ethyl Alcohol Test
  • EtOH Test

What is Ethanol Test? (Background Information)

  • Ethanol Testing is done to detect the presence and levels of alcohol in the body. The testing may be performed on blood, urine, saliva samples, or a sample of breath. It is also  known as an Alcohol Test
  • Alcohol, after consumption, gets absorbed from the intestines into the blood stream. The liver is the principal site of alcohol metabolism. The liver sequentially modifies alcohol, until it is converted to carbon dioxide and water. Some amount of ethanol is excreted via urine, or breathed-out from the lungs
  • Testing for ethanol/alcohol may be done for the following reasons:
    • Medical purposes: Evaluating an individual for ethanol toxicity; caused by consuming very large quantities of alcohol, in a short period of time
    • Legal purposes: Pertaining to violation of drinking-related laws, or for screening employees for drinking, or for insurance purposes
  • The samples for the above-mentioned purposes are collected and processed separately. Although testing is done with the help of one primary sample type, a second sample type is often used to confirm the results, or to refute the findings

What are the Clinical Indications for performing the Ethanol Test?

Indications for Ethanol Testing include:

  • Medical indications: When an individual presents with symptoms suggestive of ethanol toxicity, such as:
    • Confusion/disorientation
    • Instability
    • Decreased/irregular breathing
    • Stupor
    • Unconsciousness

Under such circumstances, Ethanol Testing may be done with other tests, to find out the probable cause of symptoms. Further tests maybe used to detect the presence of other drugs in the system, as well. For medical purposes, blood alcohol levels are usually estimated; less commonly, urine may be used as a test sample.

  • Legal indications:
    • Individuals suspected of violating drinking-related laws, such as driving under influence (DUI), to check if alcohol is a contributing factor to an accident, to detect alcohol consumption by a minor, or to check if a person on parole has been abstaining from alcohol
    • Sometimes, post-mortem Alcohol Testing is done, to determine if alcohol played a role in causing the individual’s death
    • Employers may test employees, as part of their drug screening program
    • During application for life insurance

When samples are collected for legal purposes, a strict chain of custody is to be maintained. Blood, urine, saliva, or breath of the individual, may be used as a sample.

A breathalyzer test (using breath sample) is commonly used to detect DUI. A blood/urine and less commonly a saliva sample, may be used as an alternate sample, to confirm/refute the findings.

How is the Specimen Collected for Ethanol Test?

Sample required: Blood, urine, breath, or saliva


  • A blood sample is collected by inserting a needle into a vein in the arm
  • Urine sample: Generally, two urine samples are collected. The first one is discarded and the second sample collected after a measured time interval. Sometimes, a single random sample maybe used to check for the presence of alcohol
  • A breath sample is collected by blowing into a device with a tube or balloon
  • Saliva samples are collected by using swabs

Preparation required: None

What is the Significance of the Ethanol Test Result?

  • The concentration of ethanol/alcohol in the sample indicates the degree of ethanol toxicity, which aids in medical management of the condition
  • From legal standpoint, alcohol levels are estimated to see if they fall within legally permissible limits
    • Alcohol levels of more than 80mg/dL is considered legally ‘intoxicated’, in most US states
    • Alcohol levels between 80-400mg/dL cause impairment and suppressed activity of the central nervous system
    • Alcohol levels exceeding 400mg/dL are potentially fatal

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

Breath and urine samples can be affected by factors, such as:

  • Presence of ketones in breath (in some diabetics with uncontrolled blood sugar levels), alcohol consumption in the immediate past, usage of mouthwash, cough syrups that contain alcohol (all affect breath values)
  • Increased standing time for urine samples containing glucose (as in diabetics) and some microorganisms

Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

References and Information Sources used for the Article:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: Nov. 28, 2013
Last updated: March 31, 2018