Accuracy

• The Substance Abuse and Mental Health Services Administration facilities use both urine tests and breathalyzers to determine alcohol content in the blood. SAMHSA has tested and reports no significant difference in the accuracy of the breathalyzer used by 58 percent of its facilities and the urine tests of blood alcohol concentration used by 83 percent of its facilities. The "Journal of Biological Chemistry" compared blood, breath and urine tests of alcohol content in the blood and found no significant difference in the results. The "Journal of Biological Chemistry" reports that potassium dichromate has a stable color that makes it an accurate indicator in its reduction reaction with alcohol.
  
  

Blood Alcohol

• Alcohol enters the bloodstream through the digestive system, and 10 percent of it remains unchanged. The alcohol blood solution passes through the alveoli in the lungs, and some alcohol from the lungs is exhaled into the air. Ten percent of consumed alcohol leaves the body through the breath, perspiration and urine. The remainder is broken down through metabolism at the same rate in everyone regardless of height, weight, sex, race or other such characteristics.
  
  

Ratio of Alcohol Content

• The amount of alcohol expelled from the lungs is proportional to the amount of alcohol in the blood. The ratio of alcohol exhaled to alcohol in the blood is 2,100:1, or 2,100 ml of alveolar air contains the same amount of alcohol as 1 ml of blood.
  
  

Potassium Dichromate

• Potassium dichromate is red-orange in solution in the breathalyzer. Potassium dichromate oxidizes alcohol, reducing it to acetic acid, while the potassium dichromate becomes green-blue chromium sulfate. The amount of alcohol in the solution in the breathalyzer determines the strength of the chemical reaction within it. The potassium dichromate is converted to chromium sulfate from yellow to blue to green, depending on the amount alcohol in the blood, breath or urine.
  
  

Dissipaton of Alcohol Concentration

• Alcohol is metabolized at the rate of .015 (1.5 percent) of blood alcohol concentration each hour. Thus, even an extremely high blood alcohol concentration will leave no measurable alcohol in the bloodstream after 10 hours.