Investigate Possible Causes of Error in a DUI/DWI Breath Test

If you feel a DUI/DWI breath test that you took was faulty, there are some avenues to explore to explain the results and help your case.

Steps

See if the breath test result was in the range of accepted errors. Different experts will give difference ranges of errors, but 5% or .02 or often considered fair margins of errors.
Get a second review. If you have access to the breath sample get it independently checked.
Look for causes of possible error related to the testing time and situation.
- See how much volume of air was given. Generally, the longer the blow, the higher the blow.
- Determine what your body temperature was at the time of the best. Generally, a higher breath temperature will read to a higher reading.
- See if the result was corroborated by another result at the same time/close in time.
Use retrograde extrapolation to calculate what your BAC would have been at the time of driving. Compare this result to the breath test results.
Look for faults in the machine itself. See if radio frequencies interfered with the machine. Check to see that the machine was properly calibrated. Make sure the machine detected alveolar air (lungs) as opposed to mouth alcohol.
Consider health factors. If you have GERD/acid reflux, it can cause alcohol from your stomach to enter your mouth through holes in your esophagus, and therefore give a falsely high result.

Hire a lawyer who understands the science behind breath tests as well as an expert witness.