Even if proper procedures are correctly followed in a blood or breath test, blood alcohol analysis is not a perfect process. It is generally recognized by scientists the .BAC testing has a inherent or built in “error factor. Some experts will testify to a ten percent (10%) margin of error for a blood test at any reading. Therefore, it is arguable for a margin of error at plus or minus .010 on any BAC reading. This could be the difference between a tier for conviction purposes. A good DUI lawyer will credibly cross examine the District Attorney expert on this point. Pure mechanical error is an issue that should be addressed in a DUI trial where the results are challenged.
Defense experts may also testify that there are certain human factors, separate and apart from pure mechanical error, that can be factored into the inherent margin of error. These include the issue of blood to breath ratio as well as the temperature of the human mouth. These factors may may account for different grading in situations where defendant’s blood is very close to the .08, 0.10, or 0.16 ranges. Speak with a Philadelphia DUI lawyer about challenging the breath or blood results in your criminal case on the inherent margin of error defense. For a free consultation, contact the Law Office of Mark D. Copoulos at 267-535-9776.