Evidential Blood Testing
Whenever someone is arrested for DUI in California, the law allows for a choice of tests. If they are arrested for driving under the influence of alcohol, then they are to be offered the choice between a breath and a blood test. If they arrested for driving under the influence of drugs, they have a choice between a blood and a urine test.
Of course, many drivers report that law enforcement offers dishonor the law concerning California’s implied consent rights by insisting that the person arrested submit to the officer’s choice of test for them. This can give rise to another issue, namely, suppression of the results where they are the byproduct of a pattern of law enforcement abuse by not honoring this right.
If the defendant selects a blood test, there are many issues that arise. The primary issue in blood testing relates to integrity of the sample. The test tube into which the blood sample is drawn is supposed to contain legally prescribed amounts of anticoagulant and preservative. If these aren’t there, or are there in either inadequate or excessive amounts, the integrity of the sample can be compromised. It is quite possible that, given the delays in testing that are routine, an inadequately preserved blood sample can ferment and create artificially high levels of alcohol that overstate what was actually in the driver’s system at the time of the blood draw.
Of course, a blood sample result is only accurate, if at all, for the alcohol level in the defendant at the time of the blood draw. This tells us nothing about the blood alcohol level of the driver at the time of driving, which is the only time that truly matters in a California DUI case.
There is a distinct advantage of blood testing over breath testing, in terms of defending the case, and that relates to the number of results that are produced. In a breath test, Title 17 requires that there be two breath samples produced, that are within a .02 agreement of one another, taken at least two minutes apart. In a blood test, there is just one needle stick. That means that, at its best, a blood test represents just one point in time, usually a significant period of time after driving, as opposed to two separate results from just one breath test, where, if the results are close to each other, each result serves to reinforce the other.
Other challenges with blood cases include:
• Contamination from an alcohol swab;
• Chain of custody issues;
• Not properly inverting the sample test tube, as required to properly combine the blood with the anticoagulant and preservative;
• Problems with calibration or accuracy in the blood testing equipment;
• Human error in testing.
As to human error, this is something not to be overlooked. Our office handled a case where the results came back at an amount our client said was impossible. We had the sample blood typed, and it turned out to be of a different blood type than our client. The prosecution, because of an error in the crime lab, was attempting to misattribute someone else’s blood sample to our client. Thankfully we caught the error, and the case was dismissed.