Tuesday, March 17, 2015
Oklahoma Expired Blood Test Kits: Is It Really Acceptable To Keep Using Them?
One of the tools that Oklahoma law enforcement use to gather evidence of driving under the influence (DUI) is a blood collection sample kit. This kit contains vacuum-sealed tubes, which are designed to draw in a pre-determined amount of blood which then mixes with an inorganic salt compound consisting of sodium fluoride and potassium oxalate.
Oklahoma blood test kits carry expiration dates on the vacuum-sealed tubes. There may be some confusion as to the effect these expiration dates may have if a police officer uses a tube that is beyond its expiration.
The first question is whether the expiration relates to the salt compound contained in the tube. The answer here is, “no.” The compound itself is stable. This leads to the second, and more significant inquiry: if the expiration date on the blood collection vacuum tube does not refer to the salt compound, then what does it refer to?
The expiration refers to the tube manufacturer’s warranty that the vacuum seal of the tube will maintain its integrity to a degree sufficient to draw a pre-determined amount of blood. It is the vacuum that draws the blood into the tube; but unlike the salt compound, the tube seal eventually does degrade and as it does, the amount of blood that it will draw into the tube becomes increasingly subject to uncontrolled variation.
So what does this mean to you, if you are subject to a blood draw using an expired vacuum tube?
The most significant impact of a loss of vacuum is that the amount of blood drawn into the tube may affect the ratio between the blood and the salt compound, which in turn may compromise the value of the test result when it comes to establishing whether a driver was under the influence when the blood sample was drawn. This potential volume-based skewing of the test sample is referred to as, “salting out”.
A second possible problem with a loss of vacuum integrity in the collection tube is that a compromised seal means that more than the blood sample may possibly be able to enter it. Certain commonly-found yeast bacteria, for example, may be able to enter via the degraded seal. That bacteria consumes the blood sugar, or glucose, and as a waste product produces… alcohol. That is correct: a contaminated sample due to a faulty vacuum seal can result in the production of alcohol inside the tube.
What is more, there is no way for the devices used to analyze the blood sample for alcohol content to distinguish between the alcohol that was in your blood when the sample was drawn and any bacterially-produced alcohol that was created after the draw. This can lead to a challenge of the evidentiary value of the sample itself.
Are expired blood test kits being used in Oklahoma? The answer appears to be, “Yes.” Documentation available from the state’s Board of Tests for Alcohol and Blood Influence indicates that not only are some expired test kits still in the field, but that the State Director of the Board of Tests has given the green light to keep using them.
Not every blood draw sample in Oklahoma will be subject to vacuum-seal compromise. And the state is encouraging law enforcement in the state to turn in expired test kits. But if you have been accused of DUI based in part on the result of a blood sample, the fact that some of these expired kits are apparently still in use is an avenue that your attorney will definitely need to investigate as part of your defense.