What is the breath test machine used in North Carolina? How does it work? The breath testing machine currently used in North Carolina is the Intox EC/IR II that is manufactured by Intoximeters Incorporated. North Carolina uses breath testing machines in order to estimate a person’s blood alcohol concentration. The theory behind breath testing is premised on the body’s function of its lungs to exchange gas. During a respiration, gas moves in and out of the blood and because alcohol is volatile, it can exist in a gas form. When alcohol is consumed, it enters the blood stream and eventually will circulate to the lungs where a small amount of alcohol is removed from the body which is expressed. The Intox EC/IR II is a machine that detects and measures alcohol in a person’s breath using an electric fuel cell. The machine collects a sample of breath through which an infrared energy beam is passed. The fuel cell causes a chemical reaction that produces an electrical current. The more alcohol present, the more voltage produced. The current produced by this reaction is measured by a microprocessor with a built-in secret source code and displays an approximation of overall alcohol content in grams per 210 liters of breath. The test results are displayed and then printed on the test record.