Do You Understand Breathalyzer Tests?

South Carolina DUI Lawyers

How Can a Breathalyzer Measure Blood Alcohol?

The blood releases alcohol through the breath. When you drink alcohol, the body absorbs it quite literally. It saturates tissue lining in the mouth, throat, stomach and intestines, and enters the bloodstream. When that blood circulates through the lungs, alcohol evaporates out through air sacs in the lungs. A breathalyzer measures the alcohol in the breath that is exhaled.

There’s a mathematical relationship between alcohol blood level and alcohol breath level. It was determined that the alcohol measured in the breath can tell you something about the overall alcohol content in the bloodstream. A “universal” relationship was determined between the two levels alcohol concentrations (despite the fact that each person is unique). The golden rule of breath testing says: Every 2,100 ml of air in the lungs (breath to be exhaled) will contain the same amount of alcohol concentration as 1 ml of blood.

A device that can measure alcohol in the breath, can then estimate alcohol in the blood. Breath testing devices use special technology to calculate the amount of air expelled, the amount of alcohol in that air and then calculate a blood alcohol level based on the ratio above. In South Carolina, the only permissible breath testing device is the Datamaster (DMT), which uses infrared technology to measure the alcohol content in the breath.

Are Breathalyzer Tests Admissible in Court?

Results of handheld breathalyzer tests may be used to establish probable cause or reasonable suspicion of drunk driving. This allows a police officer to make an initial arrest and bring you in for an admissible breath test or blood test.  However, although the results of a breathalyzer test may be admissible in court, the results of a breathalyzer test may also be challenged. The accuracy of a DataMaster breathalyzer depends upon the unit, the timing of the testing and the testing process for the suspected motorist. In addition, there are procedural steps that must be taken, which if omitted, may result in the results being inadmissible.

By: Pete Strom, South Carolina DUI Lawyer



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