Breath & Blood Tests

One of the most common questions that people ask us about DUIs is, “Should I take the breath test or the blood test if I am stopped by a cop for DUI.” It seems to be a common belief among many people that the breath test is the better choice in order to successfully fight your DUI case in court. The truth is, there is no universally correct answer to this questions. There are many variables that must be taken into consideration before deciding which is the better choice for purposes of establishing a defense. For a person who is not an expert, some of these variables may be very difficult to assess. To begin, we have provided a brief explanation of the breath test below.

A DUI breath-test measures the concentration of alcohol in a person’s blood. During the breath-test, a person forcefully blows into an instrument that analyzes the person’s deep lung air (also called “alveolar air”). The amount of alcohol that is present in the alveolar air is believed to correspond to the percentage of alcohol in the blood. Law enforcement agencies routinely use this breath-alcohol device, believing it to be a reliable method of measuring a person’s blood-alcohol concentration (BAC).

The most common breath-alcohol device that is used by California law enforcement agencies during DUI investigations is a handheld device called the Alco-Sensor IV. Unlike cheap and unreliable models sold to the public, this device uses a fuel-cell technology to analyze a person’s breath for the presence of alcohol. The Alco-Sensor IV is considered to be one of the most sophisticated and reliable hand-held instruments of its kind. Nevertheless, this instrument is prone to many flaws and inaccuracies, such as:

  • User error
  • Failure to follow the manufacturer’s instructions
  • Incorrect recording of test results by user
  • Improper storage
  • Improper maintenance
  • Failure to routinely calibrate the instrument
  • Improper calibration
  • Mistakenly detects the presence of trapped mouth alcohol
  • Interference by surrounding radio frequencies
  • Age of instrument

Title 17 of the California Code of Regulations provides that the officer must maintain continuous observation of a person prior to taking his/her breath sample. The manufacturer of this device also recommends a 15-20 minute observation period. This observation period allows for the dissipation of any alcohol that may be trapped in the person’s oral or nasal cavity. Although the 15 minute observation period helps reduce the risk of inaccuracies, there remain a myriad of other factors that call into question the accuracy of breath-test results.

Unfortunately, many individuals have been wrongfully convicted for drunk driving in California, based on inaccurate or unreliable breath-test results. In order to fully understand whether a breath test result is reliable, one must be properly trained in the use and functionality of this device, and have a working knowledge of its calibration procedures. In many instances, police officers who conduct these tests are neither certified nor properly educated about this device. Consequently, numerous mistakes can be made. Many of these mistakes can only be detected by a DUI expert who has a strong working knowledge of the device.

At California Criminal Defense Center, you are guaranteed representation by a highly experienced Southern California DUI lawyer who has been certified in the use and calibration of this breath-alcohol device, after completing the rigorous classroom and clinical training. You will take comfort in knowing that your DUI lawyer has also completed the DUI training courses given to California law enforcement officers.

To schedule a confidential and free consultation with our DUI lawyer, please email us by completing the Free Consultation form. You may also call us toll free at 1-800-DUI-KING (1-800-384-5464).