Blood Alcohol Level Testing Procedures

Blood Alcohol Level Testing Procedures
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  • 0:03 Driving Under the Influence
  • 0:59 Testing for Alcohol
  • 1:58 Blood Alcohol Level
  • 2:34 Testing Procedures
  • 3:35 Factors that Affect…
  • 3:58 Lesson Summary
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Lesson Transcript
Instructor: Millicent Kelly

Millicent has been teaching at the university level since 2004. She holds a Bachelor's degree in Criminal Justice and a Master's degree in Human Resources.

Blood alcohol level testing is considered to be the most accurate way to test for the presence of alcohol. This lesson will look at the different ways to test for alcohol and discuss proper procedures for blood alcohol testing.

Driving Under the Influence

Blood alcohol level testing is considered the most accurate way to test for the presence of alcohol. This lesson will look at the different ways to test for alcohol and discuss proper procedures for blood alcohol testing.

Drinking and driving can be a lethal combination. In 2009, for example, almost 11,000 motor vehicle fatalities were attributed to driving under the influence of alcohol. It's a proven fact that alcohol impairs our ability to make sound judgments. It basically slows us down and changes our reaction time when we are behind the wheel.

Yet still many drivers continue to drink and drive, and for those who get caught, there is a significant price to pay. Many drunk drivers lose their driving privileges, face costly legal actions, and some even go to jail. Because the consequences of driving while intoxicated are so severe, it's imperative that law enforcement authorities test alcohol levels accurately.

Testing for Alcohol

There are three primary testing methods used to determine if someone is under the influence of alcohol:

The first of these is breathalyzer testing. This type of testing requires an individual to blow into a device that measures alcohol in the exhaled air. It does not provide a direct measurement of blood alcohol concentration, but it is a convenient testing mechanism because the device is portable and generally accurate.

Next, there's urine testing. This test is the least accurate in determining the presence of alcohol and involves testing of a urine specimen. Studies have shown that the amount of alcohol found in urine is often vastly different than the amount found in blood.

Which brings us to blood testing. To collect a blood sample, most states require that consent be obtained, and the states levy stiff penalties against those who refuse to provide consent. Blood alcohol testing is the most accurate way of determining the alcohol concentration in the bloodstream.

Blood Alcohol Level

The concentration at which alcohol is present in the bloodstream is referred to as someone's blood alcohol level. The way in which alcohol metabolizes within the body is an individual process and varies from one person to the next. In all states, an individual who is operating a motor vehicle with a blood alcohol level above 0.08% is considered legally intoxicated and is subject to criminal sanctions. For the average person weighing, let's say, 160 pounds, this means that consuming more than three 12-ounce cans of beer puts them over the legal limit.

Testing Procedures for Blood Alcohol Level

There are certain procedures that need to be followed when collecting and testing blood alcohol levels. As mentioned earlier, most states require that written consent is obtained prior to the blood draw. After consent is obtained, the steps below should be followed to ensure the sample is valid and to prevent contamination of the specimen:

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