Blood Testing Information

Although breath testing is less expensive and provides quicker results, it is considered less reliable than a blood test for purposes of determining an individual’s BAC. For this reason, officers will seek a blood sample when making a DUI arrest. Prosecutors also relish the opportunity to present evidence of blood testing in court because it allows them to call the criminalist who tested to blood as a trial witness. Ordinarily, these individuals are qualified as experts by the judge and permitted to testify about DUI related topics completely unrelated to the test of your blood. Nevertheless, blood testing is not infallible and a skilled attorney who is knowledgeable in both the law and science behind forensic alcohol analysis can make a difference.

A currently evolving issue in Scottsdale DUI law is the collection on blood samples by police officers. Arizona law requires that blood samples be taken by a medically qualified individual. Until recently, Scottsdale police officers would have a nurse or other independent medical professional collect the sample. Today, however, many Scottsdale DUI officers have become certified as phlebotomist and are collecting blood samples themselves.

Contrary to popular belief, improper collection of a blood sample can compromise the validity of any future laboratory testing that may be conducted. If, for example, the skin was not sterilized before insertion of the needle, microscopic fungal organisms can get drawn up into the collection tube with the blood. Some of these organisms can convert your blood into alcohol and artificially inflate your BAC. The test could also be invalidated if the officer uses an isopropyl alcohol pad to sterilize the collection site.

Common Blood Testing Defenses

In addition to challenging the credentials of the police officer and the manner in which they took your blood, Scottsdale DUI Lawyer Joshua S. Davidson will thoroughly investigate your case for any other grounds to challenge your blood test results:

Chain of Custody

It is not uncommon for a blood sample to pass through the hands of several different people between the time it is obtained and the time it is testing. Moreover, Scottsdale crime lab technicians tests dozens of samples during each “run”. This process is obviously fraught with the risk of a sample being mishandled. Scottsdale DUI Attorney Joshua S. Davidson will closely analyze the chain of custody record and investigate any irregularities.

Condition of the Collection Tube

The blood kits used by Scottsdale DUI officers include sterilized vacuum tubes which contain an anticoagulant and a preservative. Because the vacuum is slowly compromised and subjected to the exposure of external contaminates over time, each tube has an expiration date by which it must be used. If the police in your case used an expired tube or failed to document the expiration date, a Scottsdale DUI defense attorney may be able to keep you blood test results out of court.

Were Proper Testing Procedures Followed?

Even if the blood is properly obtained and handled, it still needs to be analyzed by the criminalist. In Scottsdale, the preferred method of testing is gas chromatography. Mr. Davidson will closely review the records and chromatographs from your test together with any calibration tests that were conducted. A pretrial defense interview of the criminalist who actually tested your blood will also be conducted. As a Scottsdale DUI Lawyer who understands the legal and scientific complexities of blood testing, Mr. Davidson will subject the prosecution to the highest levels of scrutiny when challenging your blood test results.