Blood Alcohol Level
Reviewed
A blood alcohol test measures the amount of alcohol (ethanol) in your blood. It is commonly used to determine if alcohol is present and to what extent it is affecting you. Results can be used for legal, employment, or medical purposes.
Preparation and collection
You don't need any special preparations for this test.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- The timing of the test can affect accuracy; it can detect alcohol for up to about 12 hours after your last drink.
- Individual factors such as weight, age, sex, type of alcohol, how quickly you drank, how much you ate, medicines you're taking, and tolerance can affect your BAC and level of impairment.
- Results may be used for legal purposes; consult a lawyer if you have legal concerns.
What to do next
If you have questions or concerns about your results, talk to a health care provider and/or a lawyer.