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Should DWI Blood Tests Replace the Breathalyzer?

Driver being subject to test for alcohol content with use of breathalyzer

A Texas DWI attorney reveals everything you need to know

With faith in breathalyzer results plummeting, law enforcement is seeking to find new forms of evidence to present at DWI trials.

The formerly "bulletproof" breathalyzer results being used as driving while intoxicated (DWI) evidence has a lot of dents in its armor. The reputation of breathalyzer results is so poor that in some states, prosecutors won't even admit breath tests into evidence.

More and more, police departments are analyzing a drunk driving suspect's blood instead of breath to determine BAC (blood alcohol content) levels. The legal limit is 0.08 BAC. Some states are investing more in blood draws than others. In Georgia, the state recently won a grant to purchase equipment and train almost 100 state and local police officers on how to draw blood for BAC analysis.

Texas DWI and "No Refusal"

In Texas, the breathalyzer is still a law enforcement tool. Despite the breathalyzer's proven track record of delivering bogus results, Texas counties and communities run "No Refusal" campaigns. These temporary programs give police a little extra muscle to force people to submit to screenings.

"No Refusal" is a strategy to crack down on drunk driving by stepping up DWI enforcement, BAC testing, and arrests. The program creates special circumstances that allow for speedy access to DWI-related court warrants. If someone refuses to submit to a breath or blood BAC test during a "No Refusal" campaign, they can be forced to take one by a judge. Most "No Refusal" campaigns in Texas are held around the holidays, but Tarrant County has forced testing all year.

BAC test shortfalls

The justice system is beginning to admit breathalyzer shortfalls — and that's great. Their shift to blood tests, however, is not. Blood tests are more invasive and can scan for more than just alcohol. A blood draw done to support a driving under the influence (DUI) charge may be able to identify drugs and polysubstances, as well.

While blood tests can produce more information than those that process breath, they are open to many of the same outside factors that could destroy the accuracy of the test results.

In Michigan, the State Police, and subsequently many local police departments, stopped using breathalyzers over allegations that the equipment wasn't properly maintained. Police are accusing the company hired to calibrate the machines of providing them with fraudulent work documents. Just as breath test equipment can be in poor condition, so too can blood testing devices.

This is just one example of how blood and breath test results can be skewed.

Challenging DWI blood test results

There are a lot of ways DWI blood tests can be wrong. Drawing blood is a multi-step process that involves various equipment and many opportunities to introduce errors. Outside factors that could make DWI blood test results look worse include:

  • Improper sample handling that leads to contamination
  • Delay in time of draw and actual analysis
  • Human error
  • Defective equipment
  • Improper sample preservation that leads to fermentation
  • Inaccurate interpretation of results

We have already seen examples of how easy it is to throw off a blood test. Thousands of DWI convictions were thrown into doubt when it was discovered that police departments across the U.S. were using blood sample vials that had been recalled. Hundreds of thousands of test tubes were recalled in 2019 because some vials in the batch did not contain the chemicals necessary to preserve the samples. While many police departments were notified about the recall and returned the vials, other police departments didn't get the memo.

Legal help is available when you've been charged with DWI

At The Webb Law Firm, P.C. we have years of experience exposing unreliable BAC results. We break down seemingly "solid" evidence and reveal prosecutor tricks to get desirable outcomes for our clients. Texas hands down harsh verdicts for DWI convictions. If you are facing DWI charges or suspect they are forthcoming, contact us today for a free case evaluation with an experienced Texas DWI defense lawyer to find out how we can help you.

We proudly serve clients in the greater Houston area, Conroe, The Woodlands, Waller, and all of Montgomery County. We are ready to hear from you 24/7.