Breathalyzer and Blood Tests: Accuracy and Challenges

Law enforcement frequently uses blood tests and breathalyzers to measure a driver’s blood alcohol level (BAC) and prove impairment. These tests have a scientific basis, although they are not perfect. Anyone facing DUI accusations must comprehend the science underlying these tests, their possible flaws, and how to contest them in court. Speaking with a Colorado DUI lawyer can provide you the knowledge and experience you need to handle these challenges successfully.

The Science Behind Breathalyzer Tests

A person’s estimated blood alcohol content (BAC) is determined using a breathalyzer test. Alcohol enters the circulation through the small intestine and stomach after consumption. Alcohol evaporates into the alveolar air when blood passes through the lungs and is quantified by exhaled breath. Breathalyzers use a ratio to determine blood alcohol content (BAC), based on the typical connection between blood and breath alcohol concentrations.

  • Infrared Spectroscopy: Some breathalyzers use infrared light to detect alcohol molecules in the breath sample. The presence of alcohol absorbs specific wavelengths of infrared light, and the device measures this absorption to estimate BAC.
  • Fuel Cell Technology: Other breathalyzers use fuel cells that produce an electrical current when exposed to alcohol. The strength of the current correlates with the alcohol concentration, providing a BAC estimate.

Potential Inaccuracies of Breathalyzer Tests

Despite their scientific basis, breathalyzer tests can produce inaccurate results due to various factors:

  • Calibration Issues: Breathalyzers require regular calibration to ensure accuracy. An improperly calibrated device can yield incorrect BAC readings.
  • Mouth Alcohol: Residual alcohol in the mouth from recent consumption, mouthwash, or medication can artificially inflate BAC readings.
  • Breath Temperature: Breathalyzer accuracy can be affected by the temperature of the breath sample. Higher temperatures can result in higher BAC estimates.
  • Medical Conditions: Conditions like acid reflux or diabetes can produce compounds that interfere with breathalyzer readings, leading to false positives.

The Science Behind Blood Tests

Blood tests directly measure the alcohol concentration in a person’s bloodstream. They are generally considered more accurate than breathalyzer tests but are not without potential issues. Blood samples are typically drawn by medical professionals and analyzed in a laboratory.

  • Gas Chromatography: The most used technique for determining blood alcohol concentration is this one. The components are separated in a gas chromatograph after the blood sample is evaporated. A BAC reading is then obtained by measuring the quantity of alcohol.

Potential Inaccuracies of Blood Tests

While blood tests are often viewed as the gold standard for BAC measurement, they can still be subject to inaccuracies:

  • Contamination: Blood samples can be contaminated if not properly handled or stored, leading to erroneous results.
  • Fermentation: Improper storage can cause blood samples to ferment, artificially increasing alcohol levels.
  • Timing: The timing of the blood draw relative to when the person was driving can affect BAC readings. Alcohol absorption and elimination rates vary, and a delay in testing can result in higher or lower BAC levels than when the person was driving.

Challenging Breathalyzer and Blood Test Results in Court

Challenging Breathalyzer Results: 

A Colorado DUI attorney can challenge the results of breathalyzer and blood tests in several ways:

  • Calibration Records: Attorneys can request maintenance and calibration records for the breathalyzer device used. If the device was not properly maintained, its results may be deemed unreliable.
  • Administration Protocol: Breathalyzer tests must be administered according to specific protocols. Any deviation from these procedures can be grounds for challenging the results.
  • Medical Conditions: Demonstrating that a medical condition or medication could have affected the test results can cast doubt on their accuracy.
  • Chain of Custody: For blood tests, the chain of custody must be meticulously documented. Any gaps or mishandling in the sample’s custody can lead to questions about its integrity.
  • Expert Testimony: A DUI attorney can call on medical or forensic experts to testify about the potential inaccuracies and limitations of the testing methods used.

The Role of a Colorado DUI Attorney

Navigating the complexities of DUI charges requires specialized legal expertise. A Colorado DUI attorney can:

  • Analyze Evidence: Examine the material closely and look for any possible mistakes or flaws in the way the blood test and breathalyzer were administered.
  • Develop Defense Strategies: Create defense plans to cast doubt on the validity of test results, based on legal precedents and scientific understanding.
  • Negotiate: Engage with prosecutors to negotiate plea deals or alternative sentencing options that may mitigate the consequences of a DUI conviction.
  • Represent in Court: Make sure you are well-represented in court, that the evidence is carefully considered, and that your rights are upheld.

Although they are not perfect, breathalyzers and blood tests are essential instruments in the fight against DUI. Anyone facing DUI allegations must be aware of their scientific foundation, any potential flaws, and the legal process for contesting them. Speak with a Colorado DUI lawyer for the knowledge and experience needed to handle these situations well. You may strive toward the best possible result in your case with the correct legal assistance, ensuring that the evidence used against you is carefully examined and that your rights are respected.

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