In recent years there have been questions concerning blood testing concerning DUI cases, like the blood sample debacles and the process for testing.

When a blood sample is drawn from the suspect in a DUI case rather than using a breath machine, the sample is supposed to be inserted into a vial containing preservative and anticoagulants, then shaken and sealed.

The process requires that a chain of custody be established: the location of the vial of blood must be identifiable at all times so that it does not become contaminated or mixed up with someone else’s vial. At any stage of this chain of custody, of course, things can go wrong with the vial or the records.

The blood testing is commonly done using gas chromatograph instruments, and analyzed in large batches perhaps 40 or more which are analyzed in sequence; which is much faster and more economical than isolating, identifying and separately analyzing one vial after another.

Problems often occur in the either stage. Testing facilities must review and update their policies on the collection, identification, actual testing of the blood samples for DUI cases to prevent the problems.