MADDvocate - Winter 2009 - (Page 21)

Legally Speaking and breath sample evidence are routinely accepted by juries, but both are frequently examined and questioned in minute detail. Unlike milk or juice, the body does not digest alcohol. Instead, it is mostly absorbed by the small intestines. Once absorbed, it makes its way into the bloodstream until it is expelled through evaporation in the lungs. In the lungs, some of the alcohol passes over the lungs’ air sacs, allowing it to be released in a person’s breath. One argument disputing the results of breath testing is the lack of repeatability, the cornerstone of scientific testing. Alcohol in the breath evaporates rather quickly, making breath samples difficult to preserve for future testing. Therefore, breath testing consists of two breath samples, taken approximately three minutes apart. The two-sample concentrations must fall within .02 of each other in order to be valid. Blood tests, on the other hand, can be preserved and retested as necessary. Testing, Testing Understanding blood and breath alcohol testing Relying on Qualified Staff Another area of reliability lies in the equipment and the personnel using it. Specialized instruments are used to collect and process blood and breath samples, but the instruments don’t analyze and interpret data. Trained professionals use scientific tools that apply a proven science to fully examine and evaluate blood and breath for alcohol concentration. Several levels of integrity are required before a valid test result is produced. No matter which test is used during investigation, understanding the scientific methods used in forensic laboratories isn’t easy, and test results should be evaluated. Good scientists are finders of fact with no hidden agendas. And both blood and breath tests are universally relied on as accurate ways to measure the alcohol content in a person’s body. by Michelle O’Neal, Senior Forensic Chemist, Tarrant County Medical Examiner’s Office, Fort Worth, Texas he day is coming in this country when no one arrested under the suspicion of driving while intoxicated will be able to refuse alcohol testing—either by blood or breath testing. Both use valid scientific methods to identify the amount of alcohol in a person’s system. It is illegal in all 50 states to drive with a blood alcohol concentration (BAC) or a breath alcohol concentration (BrAC) of .08 or above. A BAC of .08 means that there are .08 grams of alcohol per 100 milliliters of blood or .08 grams of alcohol per 210 liters of breath. T Technical Questions? Are there any questions or terms you’d like explained? Send them our way, and they may be addressed in future issues of MADDvocate. Visit www.madd.org. Determining BAC/BrAC BAC and BrAC test results help juries determine whether or not a person was driving impaired. Results obtained through the analysis of blood Winter 2009 | MADDvocate http://www.madd.org

Table of Contents for the Digital Edition of MADDvocate - Winter 2009

MADDvocate - Winter 2009
Contents
Across the Nation
Court Reporting
Advocacy in Action
Insurance Crash Course
Stuck in Grief
Prepping for Surgeries
It’s Contagious
Legally Speaking
Healing Journey

MADDvocate - Winter 2009

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