Blood alcohol testing is a critical component of DWI cases. Most of the time, the outcome of the case hinges on these very results.

The term “chain of custody” refers to how a blood test sample changes hands between the time it was taken from the suspect and when it was tested in a laboratory.

For a DWI blood test to be considered reliable, the chain of custody must be well-documented.

If at any point the police can’t account for where your blood sample was or who it was with, you may be able to use this to your advantage. Here’s what to know and how a Maryland drunk driving attorney can help you build a strong defense.

What Do Prosecutors Need To Establish An Intact Chain Of Custody?

Prosecutors are well-versed in the process of BAC testing and also work with hospitals and laboratories that know how to test samples according to state law. They will usually take the following steps to obtain your sample and prove the chain of custody was unbroken:

• Document the date, time, and location of the blood draw
• Record the name of the person who did the draw and any police officers who were present for it
• Record the name of any people who took the blood sample from the testing site to the laboratory
• Document each time the blood sample was transferred from one person to another

Prosecutors will also need to prove that the testing equipment was properly calibrated and that the appropriate steps to perform the test were taken.

Challenging The Chain Of Custody In DWI Cases

If the police took a blood sample, a qualified DWI attorney will immediately begin to deconstruct the collection process and look for possible holes in the chain of custody.

In the event that police can’t account for the sample or how it was tested at any point throughout the process, your lawyer will move to have this evidence thrown out. Without it, prosecutors will have to find something else to prove that you were driving drunk. This is often hard to do in retrospect.

Get Qualified Legal Help From A Maryland DWI Lawyer Now

Richard Brueckner is an experienced Maryland drunk driving lawyer that can help you fight back after a DWI arrest. Call now for a consultation at 410-430-1464.