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What Impacts BAC vs. BrAC Results

Drivers who were pulled over by a police officer for drinking and driving may have heard of the acronyms BAC and BrAC, but don’t know what they mean. We’re going to explain how they’re measured and what can impact the results. Drivers with any questions should have them answered here, but if any readers still have questions, an Intoxalock state specialist can help answer them.

What’s the Difference Between Blood Alcohol Content (BAC) and Breath Alcohol Content (BrAC)?

The two methods of measuring alcohol contents in the body are similar, but there are key differences. Let’s break it down.

  • Blood Alcohol Content (BAC) - this is a measurement of alcohol intoxication. If someone has a BAC of .10, or one-tenth of a percent, this means that they have .10 grams of alcohol per 100 ml of blood, or 1 part alcohol for every 1,000 parts blood, in their system. In most states, .08 is considered legally intoxicated, while 0.0 is sober. Anything above .40 is potentially fatal. BAC alcohol can be measured with urine or blood tests, or extrapolated from a breathalyzer test.
  • Breath Alcohol Content (BrAC) - BrAC also measures the amount of alcohol in your system, but it does so by measuring alcohol in your exhalations. When you drink alcohol, it’s absorbed into your bloodstream and carried onward to your brain and lungs. Thus, alcohol will be in your breath when you exhale after drinking. A BrAC device will measure the amount of alcohol in your breath and use it to estimate your Blood Alcohol Content. When using an ignition interlock device (IID) to measure BrAC, any amount of alcohol in the system results in a failed test.

BrAC is used as an estimate to get to Blood Alcohol Content, which is measured using more precise blood or urine tests to get the most accurate results.

There are many guidelines regarding how many drinks you can have and still be under the legal limit, such as one drink per hour, etc., but these guidelines are general and don’t account for all the differences in body type and metabolism. The best way to avoid driving while intoxicated is to stay sober if you’re driving, or find an alternative way to get home if you’re unsure you can drive safely.

How is Blood Alcohol Content Measured and What Impacts Results?

Blood alcohol content is measured via a blood, breath, or urine test. It measures the parts of alcohol per 1,000 parts of blood. A rating of 0.0 is sober, and 0.08 is legally impaired. However, people start to feel the effect of alcohol at just 0.02 percent BAC. Judgment is impaired, and you are easily distracted and not able to keep up with tasks.

Many things can impact your BAC alcohol level and how you metabolize alcohol, such as:

  • Drinking on an empty stomach - If your stomach is full of food, this helps keep the alcohol you drink in your stomach longer, preventing it from spreading as quickly through your bloodstream. This is why those who drink on an empty stomach feel the effects of alcohol more quickly.
  • Time - Everyone metabolizes alcohol differently, but spreading out your drinks throughout the night will keep your BAC lower than if you drank them in a short time.
  • Breathing pattern - Holding your breath or hyperventilating (breathing very rapidly) can impact your test results.
  • Medication - Prescription medications or other recreational drugs can interact with alcohol and cause you to be more impacted by drinking.

    What is BrAC and What Can Impact Measurement?

    Breath alcohol content is typically measured by a breathalyzer or ignition interlock device. It measures the amount of alcohol in the air you breathe out and uses that to estimate your blood alcohol content.

    When you have an ignition interlock device installed, you’ll need to test your BrAC and pass in order to start your car. Anything above 0.0 percent is a failed test. There are many factors that can impact your results. Of course, drinking is one of them but other benign activities can impact your rating too, so it’s best to be careful. Here are some common things that impact test results:

    • Mouthwash or breath sprays - Mouthwash products and breath sprays often contain a small amount of alcohol, and this can impact your test results. Since it’s going directly into your mouth and then you are breathing out to test, your BrAC may register higher on the device.
    • Food - Certain types of fruit, energy bars, and spices may interfere with the test. If you’re concerned, it’s a good idea to drink water and wait a 15 minutes before testing.
    • Smoking - Cigarette smoking impacts the way your body absorbs alcohol and could affect the test result.
    • Medical conditions - Conditions like acid reflux or GERD can cause stomach contents to reverse course and head back up the esophagus. If this includes undigested alcohol it could impact the test results.
    • Medical conditions - Conditions like acid reflux or GERD can cause stomach contents to reverse course and head back up the esophagus. If this includes undigested alcohol it could impact the test results.
    • Wiper fluid - When you use wiper fluid, chemicals are released into the air and could impact the test results, because you’re breathing them in and out. If you need to clear your windshield, you may want to take the test first.

    How to Avoid Failing a BrAC or BAC Test

    If you’ve already committed an alcohol-related driving offense and have an ignition interlock device installed, you have to regularly use your IID to test your BrAC. All failures are reported, so it’s understandable to be concerned about potential contaminants.

    In order to avoid failing either test, you should:

    • Drink responsibly - if you’re driving, the best way to pass the test is to stay sober. However, if you want to drink it will help if you space out your drinks, limit the amount of drinks, and also make sure you’re eating and not drinking on an empty stomach.
    • Rinse and wait - since foods can sometimes impact the test, it’s a good idea to rinse your mouth with water and wait 15 minutes after eating to take your BrAC test.
    • Don’t drive - if you’ve consumed alcohol, get a safe ride home instead.

    What to Do if You’ve Recently Failed a BAC Test

    If you’ve recently failed a blood alcohol test and are dealing with a DUI conviction, Intoxalock can help. In some cases, the court may have mandated an ignition interlock device be installed. An Intoxalock state specialist can guide you through the process and help you find an installation location near you. Contact us for help today.


Category: Drunk Driving

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