Blood Alcohol Test for Your Teen: About This Test

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What is it?

A blood alcohol test measures the amount of alcohol in your teen's body. This measurement is called the blood alcohol concentration, or BAC.

The blood alcohol test measures only the amount of alcohol in the blood at the time the sample is taken. It does not show how long your teen has been drinking or whether your teen has an alcohol-use problem.

Why is this test 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.
  • Find the cause of an altered state of mind, such as unclear thinking, confusion, or coma.
  • See if your teen is using alcohol.

How is the test done?

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

When should you call for help?

Call 911 anytime you think your teen may need emergency care. For example, call if:

  • Your teen seems confused and is seeing things that are not there.
  • Your teen has a seizure.
  • Your teen vomits blood or what looks like coffee grounds.
  • You're worried your teen can't stop from hurting themself or someone else.

Where to get help 24 hours a day, 7 days a week

If your teen talks about suicide, self-harm, a mental health crisis, a substance use crisis, or any other kind of emotional distress, get help right away. You can:

  • Call the Suicide and Crisis Lifeline at 988.
  • Call 1-800-273-TALK (1-800-273-8255).
  • Text HOME to 741741 to access the Crisis Text Line.

Consider saving these numbers in your phone.

Go to for more information or to chat online.

Call your doctor now or seek immediate medical care if:

  • Your teen has trembling, restlessness, sweating, and other withdrawal symptoms that are new or that get worse.
  • Your teen's withdrawal symptoms come back after not bothering your teen for days or weeks.
  • Your teen cannot stop vomiting.

Watch closely for changes in your teen's health, and be sure to contact your doctor if:

  • Your teen needs help to stop drinking.

Follow-up care is a key part of your teen's treatment and safety. Be sure to make and go to all appointments, and call your doctor if your teen is having problems. It's also a good idea to keep a list of the medicines your teen takes. Ask your doctor when you can expect to have the test results.

Where can you learn more?

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The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.