Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Substance Abuse and Addiction Health Center

Font Size

Self-Test for Breath Alcohol

A breath alcohol test is an estimate of your blood alcohol concentration (BAC). The test measures the amount of alcohol in the air that you breathe out (exhale).

You can measure your own breath alcohol level with a simple handheld device. If the device is calibrated and used according to the manufacturer's directions, it can provide an accurate estimate of your blood alcohol level. There are different types of devices available. You can get simple devices meant for home use and professional devices like those used by police for suspected drunk drivers.

Within minutes after you drink alcohol, your blood alcohol concentration starts to rise. Unlike food, alcohol is absorbed directly through the walls of the stomach, goes into the bloodstream, and travels throughout your body and to your brain. This allows blood alcohol levels to increase quickly.

The amount of alcohol in your blood reaches its highest level about 60 minutes after you drink. But food in your stomach may increase the amount of time it takes for the blood alcohol to reach its highest level. Most of the alcohol is broken down in the liver camera.gif. The rest of it is passed out of your body in urine and your exhaled breath.

You can buy breath alcohol devices to measure your BAC at many pharmacies or through the Internet.

  • The manual device is a glass tube (or a balloon and a glass tube) containing crystals that change color when exposed to alcohol from your breath. This device is less expensive than electronic meters.
  • The electronic meter shows your BAC in a digital display window after you blow into a glass mouthpiece attached to the meter. This type of meter is more expensive than the manual type.

Many bars and restaurants provide their customers with free alcohol breath tests using one of these two methods. The devices are also used to monitor people in an alcohol rehabilitation center or hospital.

Why It Is Done

The breath alcohol self-test is used to estimate your blood alcohol concentration (BAC). The results can help you decide whether it is safe to drive. This estimate of blood alcohol is not intended to represent your actual driving abilities. Your driving may be impaired even with a low BAC level, such as below 0.05.

1 | 2 | 3 | 4 | 5

WebMD Medical Reference from Healthwise

Last Updated: September 09, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

Today on WebMD

child ignored by parents
prescription pain pills
Woman experiencing withdrawal symptoms
Teen girl huddled outside house
Man with glass of scotch
overturned shot glass
assortment of medication
Depressed and hurting