The Legal Partners

You Can Trust

What is blood alcohol concentration?

On Behalf of | Apr 28, 2023 | DUI |

When you are stopped for driving under the influence (DUI) of alcohol, the police will measure your blood alcohol concentration (BAC) using a breathalyzer test. In Kentucky, it’s illegal to drive with a BAC of 0.08% or higher and 0.02% or more for drivers under 21.

This guide discusses what you need to know about BAC:

The amount of alcohol in your blood

As the name suggests, BAC is the amount of alcohol in your blood. When you drink alcohol, it will enter your bloodstream through capillaries. A significant percentage is absorbed into the bloodstream through the small intestines and some through the stomach. When you take a breathalyzer test, the amount of alcohol in your blood can be detected. 

Breathalyzers express the weight of ethanol in grams per 210 liters of breath or 100 milliliters of blood (the ratio of breath alcohol to blood alcohol is 2,100:1). Thus, a BAC of 0.08% means your blood contains 0.08% alcohol by volume.  

Factors that affect the BAC level 

Undoubtedly, the number of drinks determines one’s BAC level. However, some factors may lead to different results when two people have the same number of drinks. They include: 

  • Weight 
  • Gender 
  • Food eaten before drinks 
  • Tolerance levels 
  • Metabolism 

Thus, it may not be the best idea to only depend on the number of drinks as an accurate indicator of impairment. A driver may have one glass of wine and record a higher result than someone who drank more. 

Can you get a false reading?

A breathalyzer test can give a false reading if it has mechanical issues or it was poorly calibrated. Medications and medical conditions may also do this.

If you are charged with a DUI, it can help to get legal guidance to determine the best defense strategies to protect your record.