It’s no secret that BAC tests don’t always yield the correct results. In some situations, inaccurate results from breathalyzers or blood testing can lead to people being convicted of a crime they never committed. It’s an unfortunate reality that many people have come face to face with over the years.

What can affect a blood alcohol test? What is it about current blood alcohol testing methods that makes them so prone to error? While there are a slew of various reasons a BAC test could go wrong, let’s take a quick look at the top 5.

1. Your blood alcohol concentration rises over time

Your BAC will gradually rise over time. In other words, the alcohol doesn’t hit you all at once. Here’s an example of where this concept can cause problems:

You leave the bar, and you are within the Texas legal alcohol limit to drive. On your way home, you are pulled over by an officer. You decide to take a blood test. Once you are taken in and your blood test is initiated, your BAC has risen to a level not within the legal limit. Now, you will be charged with the crime of drinking and driving. 

If the officer had never pulled you over, would you have made it home before your BAC was too high? There’s currently no law in place that accounts for this issue.

2. BAC test equipment isn’t always up to the task

Ever wondered “How accurate is a BAC blood test?” Unfortunately, these tests are only as accurate as the equipment used to take them. 

Whether we’re talking about breathalyzers or blood tests, the equipment itself has been known to cause problems. And when these faults are combined with human error and the aforementioned issues with timing, the results are, quite simply, more unreliable than many would care to admit. 

Although a blood test for alcohol use isn’t typically the most accurate, breathalyzers are a different story. This is also why we believe that “do not blow” is bad advice; it’s easier to beat a breathalyzer test in court than it is to beat a blood test.

To perform correctly, breathalyzers require regular tuning. Officers may not always perform this necessary maintenance. Another problem with breathalyzers exists in the fact that they pick up different substances and incorrectly report those substances as alcohol (more on this in a bit).

Blood tests are also capable of reporting inaccurate results based on faulty equipment. As mentioned earlier, equipment needs to be up-to-standards at all times. However, inaccuracies in blood alcohol testing typically aren’t associated with the equipment itself but with that of the who, where, and when (for example, storage, training, and various other protocols). 

3. All officers are not trained equally.

People make mistakes all the time, and as we are all well aware, police officers are not immune to this very human problem. When you take officers (whether they’re experienced or not) and you place them in a high-pressure situation (like in a field sobriety test), there are bound to be mistakes.

This is why it is incredibly important for officers to receive proper and routine training on how to conduct themselves and the equipment during a BAC test. Officers need to be aware of the very real prospect that results can be (and often will be) inaccurate from a BAC test. They need to address every situation from a variety of angles, and not just assume that the test knows all.

However, this goes beyond simple breathalyzers. There’s always the possibility that full-blown blood tests can be mishandled, as well. During blood alcohol testing methods, contamination, improper storage, or even mislabeling can occur, making the results completely unreliable. 

But who’s to even say that any mistakes occurred? Unless you have a board-certified DWI specialist at your side, proving issues during a BAC test can be difficult.

4. Cops can make bad judgment calls

Aside from police officers being trained improperly and unknowingly making mistakes during a BAC test, the unfortunate reality is that sometimes cops knowingly make the wrong call. Officers are only human, and even though we hold them to a higher standard, they don’t always live up to that standard.

Officers have been known to let drunk people go and have also been known to take in completely sober people for blood testing. They can make any call they want to when they’re out in the field; it’s up to your lawyer to make sure that bad judgment call doesn’t negatively impact the rest of your life.

5. Your body can mess with the BAC testing process

There are many common situations that can result in inaccurate reporting during a BAC test. Many of these situations are so common, in fact, that it’s surprising that breathalyzers are still allowed in the field.

Here are some situations that can lead to inaccurate results:

  • Consumption of breath mints
  • Recently brushing your teeth
  • Hypoglycemia (higher acetone levels)
  • Various diets (typically low-carb diets)
  • Your metabolism
  • Burping
  • Hiccuping
  • Vomiting
  • Alcohol leftover in your mouth

Charged with a DWI in Houston? Worried about your BAC test?

If you’ve been charged with a DWI and you submitted to a BAC test, then you’ll need a qualified Houston DWI attorney in your corner. This is especially true if you were involved in a DWI accident in which someone lost their life — in which case you will want to look for a qualified Houston intoxication manslaughter lawyer.

At Thiessen Law Firm, we’re Board Certified in DWI Defense by the National College for DUI Defense. In fact, Mark is one of only three lawyers in all of Texas to be Board Certified in Criminal Law by TBLS and DWI Law by NCDD. He has secured thousands of dismissals for his clients and won over 100 Not Guilty verdicts. 

Mark is also one of around 25 lawyers in the state to have been designated by the ACS as a qualified Lawyer-Scientist. In other words, he is uniquely qualified to identify, investigate, and defend you against faulty BAC test results. 

Contact us today at 713-864-9000 or use our online form to request a free consultation. 

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Thiessen Law Firm

Mark Thiessen is an aggressive trial lawyer best known for his devotion to justice for his clients and high rank as a DWI Super Lawyer in Texas.