BAC Tests In Dallas DUI Texas

There are two types of chemical tests that are typically administered to determine blood alcohol levels. A Breath test is the most common and the alternative test is the blood test.

Breath Test ::.

Technical Issues that a Dallas dui attorney will inquire about are as follows:

Last date the machine was calibrated
Up to date certification of the person operating the machine
Potential Recalls on the Machine
Standard Deviation for the test sample of the machine / Number of Standard Deviations applied for margin of error
Service Records for the Machine

For a Blood Test the technical issues are as follows :

Serum or Whole blood Test ::.

Conversion factor used in converting serum into whole blood sample
Calibration data for the lab instrument testing the alcohol level
Margin for error for the machine
Standard Deviation for the test sample of the machine / Standard deviation applied to margin of error
Prep for blood draw match protocol prepared by the doctor
Chain of custody of the sample

Always ask to retest a serum sample, especially if no blood preservative was used, this is because the sample will increase its alcohol level over time. This is for two reasons:

Blood platelets will begin adhering to the side of the vial
The glucose in the blood will begin fermenting

Remember it only a minute amount of alcohol in the blood stream to greatly alter the test results. The retest will result in a much higher BAC level. The prosecution will therefore have to explain that due to the blood sample sitting the alcohol level increased over time. The defense will be able to point out two major issues with this:

The hospital could have added a blood preservative and did not do so jeopardizing the ability for the person to defend themselves.
Clearly for some reason the blood sample increase in alcohol level once it leaves the human body. It is impossible to say how much the alcohol level increased from the time the blood sample left the body until the time it was initially tested. (but clearly it does go up)

Calibration data for the lab instrument testing the alcohol level :

Margin for error for the machine
Standard Deviation for the test sample of the machine / Standard deviation applied to margin of error
Prep for blood draw match protocol prepared by the doctor
Chain of custody of the sample

The key target with a Whole Blood sample is the chain of custody. This is critical because often times the lab used for the Whole Blood test is at a different lab then the facility taking the blood sample. The potential for a chain of custody issue occurring at trial becomes far greater for the prosecution and can represent an expensive proposition for the state if the lab they have employed is out of state and they are forced to pay lab technicians in the chain of custody to appear in court.