Many states require the officer to obtain two tests from the arrested subject, 15 minutes apart, with both tests to be within a range of .002 percent of each other to ensure scientific accuracy. Missouri, however, is a single-test state.

Breath tests are not exempt from the science procedures used in all good analytical testing. Breath tests need to be confirmed, duplicated and controlled. Quality assurance is a necessity in breath testing. Scientific safeguards are essential to assure accuracy in breath testing. Although Missouri does not require two tests for confirmation, and duplicity to ensure accuracy, the following essential safeguards are required:

  1. A pretest, 15-minute observation period
  2. Blank tests before and after the subject sample
  3. Maintenance and calibration within 35 days of the sample

The most common errors that occur in breath testing:

  1. A lack of 15-minute observation period
  2. Burping/belching during observation period
  3. Residual mouth alcohol by oral intake such as gum
  4. Temperature considerations, variations in subjects body temperature
  5. Contamination of the sample containing volatiles from exposure to paints, solvents, gasoline, diesel fuel, acetone or other exogenous factors
  6. Improper maintenance and calibration of the instrument

One must spend time with the alcohol influence report, breath test print out and maintenance report. In all cases involving breath or blood tests, a defense expert should be utilized. Do not rely on the state's expert to try and put forward your theory as to the deficiencies of the scientific tests. If you use someone else's mule, you will be kicked.

Travis Noble is a graduate of the National College for DUI Defense at Harvard University, and he lectures at seminars nationwide on DWI/DUI topics. He is the lawyer whom other lawyers consult to defend their DWI clients. Most importantly, he has a track record of successfully defending some of the toughest DWI cases in Missouri and beyond.

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