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Also known as: Ethyl Alcohol; Alcohol; EtOH; Blood Alcohol Level; BAL; Blood Alcohol Content; BAC
Formal name: Ethanol

The Test Sample

What is being tested?

Ethanol is the intoxicating ingredient in alcoholic beverages such as beer, wine, and liquor. This test measures the amount of ethanol in the blood, urine, breath, or saliva.

When ethanol is consumed, the gastrointestinal tract absorbs it. Ethanol is then carried throughout the body in the blood. The body eliminates small amounts of ethanol in the urine or from the lungs upon exhalation, but the liver processes (metabolizes) most ethanol.

The liver can process about one drink an hour, with one drink being defined as the amount of ethanol in 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of whisky. A person who drinks more than one drink an hour will have an increased level of ethanol in the blood. However, certain factors affect the metabolism of alcohol, especially the amount of food consumed prior to and during drinking. The degree of a person's intoxication can vary with age, gender, weight, and whether he or she has taken other drugs that interact with alcohol.

Drinking alcoholic beverages faster than the liver can process can result in an elevated level of ethanol in the blood. This leads to signs and symptoms of intoxication such as bloodshot eyes, flushed face, slurred speech, slow response to questions or comments, impaired judgment, decreased motor skills, drowsiness or falling asleep, and/or vomiting.

With a very high blood ethanol, more serious signs and symptoms of toxicity may appear such as confusion, stupor, staggering, irregular or slow breathing, loss of consciousness, seizures, and low body temperature (hypothermia). A very high blood ethanol can be fatal.

Long-term, excessive alcohol use can lead to the development of several medical problems such as liver disease, cardiovascular problems, depression and anxiety. (Read more about this in the article on Alcoholism.)

How is the sample collected for testing?

A blood sample is obtained by inserting a needle into a vein in the arm. A breath sample is collected by blowing into a tube or balloon. Urine samples are collected in plastic containers. Sometimes a single urine sample is collected and sometimes two separate samples may be collected with the first discarded and the second collected after a measured time. Saliva samples are often collected from the mouth using a swab.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.