DWIDataMaster cdm Breathalyzer Information
Like most evidentiary breath testing units, a test subject is required to provide breath samples by blowing into a mouthpiece and tube connected to the DataMaster cdm. The DataMaster cdm begins sampling the breath at a rate of four times per second to verify that the test subject is providing a valid sample. A valid sample is considered one in which the test subject blows a consistent and deep breath in order to obtain breath from the lower levels of the lungs where alcohol\ethanol concentrations are at their highest. The longer the subject blows, the higher the alcohol content of the tested sample. The intent is to obtain a sample in which the highest Breath Alcohol Content (BAC) can be obtained. While subjects should initially be informed to take a deep breath and blow long and deep, many subjects are informed that they need to blow harder or deeper on the second test. This is often why a subject's first and second Blood Alcohol Level (BAL) test results vary so greatly.
Between the first and second breath test to determine Breath Alcohol Content (BAC), the DataMaster cdm conducts a "control" test on a solution of water and alcohol in a 1:10 ratio. The results should register between .90 and .110 for the control. This indicates that the DataMaster cdm unit appears to be functioning properly and becomes part of the evidence ticket. Additionally, many states require that defendants give two breath samples that are within 0.020 of one another. This is designed to reduce the opportunity for the DataMaster cdm or the operator administering the test to generate inaccurate results.
While the DataMaster cdm is used by law enforcement to determine Blood Alcohol Level (BAL) and is approved to provide evidence in the prosecution of an individual suspected of Driving While Intoxicated (DWI) or Driving Under the Influence (DUI), it is not the most accurate method of determining the alcohol content in a breath sample. The commonly accepted ultimate "Gold Standard" is gas chromatography.
There are numerous factors which can contribute to a "false positive" or incorrectly high or low Breath Alcohol Content (BAC) reading in these types of devices. While the manufacturers claim sufficient safe-guards are built into the device to eliminate these factors, they are unwilling to reveal the formula and equations used by the machine to eliminate error. This is often a source of scrutiny by a qualified defense attorney in the defense of a Driving While Intoxicated (DWI) or Driving Under the Influence (DUI) case.
