Blood Alcohol Level

Blood Alcohol Level

Blood alcohol level is the measure of the amount of alcohol present in the bloodstream. It is made up of a percentage of alcohol by volume (ABV) of an alcoholic beverage, or by the amount of alcohol concentration in the body. A blood alcohol content (BAC) test is used to measure the amount of alcohol in the blood, and is a reliable way to determine if someone has been drinking excessively.


In order for an accurate blood alcohol test to be taken, the individual should be properly prepped. This includes fasting for eight to 12 hours prior to taking the test, abstaining from smoking, eating, and drinking anything alcoholic for at least two hours before the test.


When ready, a saliva sample will be taken from the individual’s mouth, and then collected in a test tube provided by a laboratory. The sample will then be analyzed for alcohol concentration and the results will be returned to the individual in the form of a blood alcohol reading.


There are two main types of blood alcohol tests: an ethyl alcohol/BAC test and a fuel cell test. An ethyl alcohol/BAC test is a chemical analysis of the saliva sample, and is the most commonly used test. A fuel cell test is an electrochemical test which is less sensitive than an ethyl alcohol/BAC test and may indicate a lower blood alcohol level, if any.


Although a blood alcohol test can accurately identify if someone has been drinking, it does not provide a precise measure of how much alcohol they have consumed. This means that someone could have an elevated BAC without actually being intoxicated. Additionally, there are several factors that could affect the accuracy of a blood test, including age, health, and medication.

Why do a Blood Alcohol Test?

A blood alcohol test is usually required when someone is suspected of driving under the influence of alcohol. It's also used to identify chronic alcohol use, as well as to monitor people entering and exiting rehabilitation programs. In some states, blood alcohol tests are also used to determine if someone is legally able to purchase and consume alcohol.

When to do a Blood Alcohol Test

A blood alcohol test can be done at any time and is usually done when a person is suspected of being under the influence of alcohol. The results of a blood alcohol test are used to determine if someone is legally able to purchase and consume alcohol, as well as to identify those who are abusing alcohol.