Skip to main navigation Skip to main content Skip to footer For Medicare For Providers For Brokers For Employers Español For Individuals & Families: For Individuals & Families Medical Dental Other Supplemental Explore coverage through work How to Buy Health Insurance Types of Dental Insurance Open Enrollment vs. Special Enrollment See all topics Shop for Medicare plans Member Guide Find a Doctor Log in to myCigna
Home Knowledge Center Wellness Library Blood Alcohol Test

Blood Alcohol Test

Test Overview

A blood alcohol test measures the amount of alcohol (ethanol) in your body. Alcohol is quickly absorbed into the blood and can be measured within minutes of having an alcoholic drink. The amount of alcohol in the blood reaches its highest level about an hour after drinking. But food in the stomach may increase the amount of time it takes for the blood alcohol to reach its highest level. About 90% of alcohol is broken down in the liver. The rest of it is passed out of the body in urine and your exhaled breath.

Alcohol has a noticeable effect on the body, even when consumed in small amounts. In large amounts, alcohol acts as a sedative and depresses the central nervous system.

A blood alcohol test is often used to find out whether you are legally drunk or intoxicated. If this test is being done for legal reasons, a consent form may be required, but refusing to take the test may have legal consequences.

Why It Is Done

Why It Is Done

A test for blood alcohol level is done to:

  • Check the amount of alcohol in the blood when a person is suspected of being legally drunk (intoxicated). Symptoms of alcohol intoxication include confusion, lack of coordination, unsteadiness that makes it hard to stand or walk, or erratic or unsafe driving.
  • Find the cause of altered mental status, such as unclear thinking, confusion, or coma.
  • Check to see whether alcohol is present in the blood at times when the consumption of alcohol is prohibited—for example, in underage people suspected of drinking or in people enrolled in an alcohol treatment program.
How To Prepare

How To Prepare

In general, there's nothing you have to do before this test, unless your doctor tells you to.

How It Is Done

How It Is Done

A health professional uses a needle to take a blood sample, usually from the arm.

How It Feels

How It Feels

When a blood sample is taken, you may feel nothing at all from the needle. Or you might feel a quick sting or pinch.

Risks

Risks

There is very little chance of having a problem from this test. When a blood sample is taken, a small bruise may form at the site.

Results

Results

Most states consider a person 21 or older legally drunk when the blood alcohol concentration (BAC) is 0.08 or greater. But the legal BAC limit for people under age 21 may be lower, such as 0.02.

Blood alcohol

Normal:

No alcohol is found in the blood.

Abnormal:

Any alcohol is found in the blood.

Effects of drinking alcohol

Having any amount of alcohol in the blood can cause poor judgment and slowed reflexes. BAC and the effects of drinking alcohol vary from person to person and depend upon body weight, the amount of food eaten while drinking, and each person's ability to tolerate alcohol.

Effects of drinking alcohol

Estimated blood alcohol concentration (BAC)

Observable effects

0.02

Relaxation, slight body warmth

0.05

Sedation, slowed reaction time

0.10

Slurred speech, poor coordination, slowed thinking

0.20

Trouble walking, double vision, nausea, vomiting

0.30

May pass out, tremors, memory loss, cool body temperature

0.40

Trouble breathing, coma, possible death

0.50 and greater

Death

Blood alcohol concentration (BAC) is a measurement of how much alcohol you have in your body. This can be used to determine when someone is legally intoxicated (drunk).

Most states consider a person 21 or older legally drunk when the BAC is 0.08 or greater. But the legal BAC limit for people under age 21 may be lower, such as 0.02.

If alcohol is found in your blood, the BAC can range from very little, such as a BAC of 0.02, to a BAC of more than 0.50. A BAC of 0.50 is very high and can cause death.

Here are some examples of BAC and its effect:

  • 0.05: Slowed reaction time
  • 0.10: Slurred speech
  • 0.20: Hard to walk, nausea, vomiting
  • 0.40: Possible coma and death

What affects BAC

BAC depends on the number of drinks you have and the strength of alcohol (proof or percentage) in the drinks. Other things that affect blood alcohol levels include:

How fast you drink.
As you increase the number of drinks per hour, your blood alcohol level steadily increases.
Your weight.
The more you weigh, the more water you have in your body. The water dilutes the alcohol and lowers the blood alcohol level.
Your sex.
Women's bodies usually have less water and more fat than men's bodies. Alcohol does not go into fat cells as well as other cells, so women tend to keep more alcohol in their blood than men do. Also, a woman's hormones may affect the breakdown of alcohol.
Your metabolism.
This is how fast your body breaks down the alcohol. Different people metabolize alcohol at different rates.
Your age.
One drink raises the blood alcohol level of an older adult more than it does for a young adult.
Food.
Food in the stomach absorbs some of the alcohol. The blood alcohol level will be higher if you do not eat before or while you drink.
Medicines or drugs.
A person who drinks alcohol and takes certain medicines, such as antihistamines or sedatives (tranquilizers), may feel more of the effects of alcohol. Also, a person who uses other drugs, such as marijuana, will feel the effects of both drugs more than if the drugs were used separately.

This information does not replace the advice of a doctor. Healthwise, Incorporated, disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. Learn how we develop our content.

© 1995-2022 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.

Related Links

Medical Tests: Questions to Ask the Doctor

<cipublic-spinner variant="large"><span>Loading…</span></cipublic-spinner>

Page Footer

I want to...

Get an ID card File a claim View my claims and EOBs Check coverage under my plan See prescription drug list Find an in-network doctor, dentist, or facility Find a form Find 1095-B tax form information View the Cigna Glossary Contact Cigna

Audiences

Individuals and Families Medicare Employers Brokers Providers

Secure Member Sites

myCigna member portal Health Care Provider portal Cigna for Employers Client Resource Portal Cigna for Brokers

Cigna Company Information

About Cigna Company Profile Careers Newsroom Investors Suppliers Third Party Administrators International Evernorth

 Cigna. All rights reserved.

Privacy Legal Product Disclosures Cigna Company Names Customer Rights Accessibility Non-Discrimination Notice [PDF] Language Assistance [PDF] Report Fraud Sitemap

Disclaimer

Individual and family medical and dental insurance plans are insured by Cigna Health and Life Insurance Company (CHLIC), Cigna HealthCare of Arizona, Inc., Cigna HealthCare of Illinois, Inc., and Cigna HealthCare of North Carolina, Inc. Group health insurance and health benefit plans are insured or administered by CHLIC, Connecticut General Life Insurance Company (CGLIC), or their affiliates (see a listing of the legal entities  that insure or administer group HMO, dental HMO, and other products or services in your state). Accidental Injury, Critical Illness, and Hospital Care plans or insurance policies are distributed exclusively by or through operating subsidiaries of Cigna Corporation, are administered by Cigna Health and Life Insurance Company, and are insured by either (i) Cigna Health and Life Insurance Company (Bloomfield, CT); (ii) Life Insurance Company of North America (“LINA”) (Philadelphia, PA); or (iii) New York Life Group Insurance Company of NY (“NYLGICNY”) (New York, NY), formerly known as Cigna Life Insurance Company of New York. The Cigna name, logo, and other Cigna marks are owned by Cigna Intellectual Property, Inc. LINA and NYLGICNY are not affiliates of Cigna.

All insurance policies and group benefit plans contain exclusions and limitations. For availability, costs and complete details of coverage, contact a licensed agent or Cigna sales representative. This website is not intended for residents of New Mexico.

Selecting these links will take you away from Cigna.com to another website, which may be a non-Cigna website. Cigna may not control the content or links of non-Cigna websites. Details