As a Washington, DC DUI lawyer, I would like to discuss the many problems with the use of urine testing to determine a driver’s blood alcohol concentration (BAC). Let’s talk about how the sample is actually collected before we deal with the “science” behind urinalysis. When a DUI suspect is arrested, after he or she has been given field sobriety tests, they are put in the back of scout car (what MPD calls their police cars) and taken to the local district station. At this point, they are booked, asked incriminating questions, probably without being read their constitutional rights, and then placed in a cell. The booking officer will then inform the driver that there is an implied consent law in the District and he or she must give a urine sample or loose his or her driving privileges for one year. If the driver agrees, he or she will sign a statement and be handed a cup in which to urinate. At this point, the officer is watching the driver try to urinate into a cup. If he can’t go in a minute or two, he is sometimes told to wait for a few minutes. After the few minutes pass, he is told to try again. If the driver still can’t go, he is considered to have refused the test. This doesn’t seem right, but that is their standard practice. This can be challenged in court during a DUI trial.
Now let’s assume the driver does give a sample. What happens to the cup of urine after it is handed to the cellblock officer. It is bagged and tagged, supposedly placed in a special refrigerator until it is transported to the Office of the Chief Medical Officer (OCME) for the District of Columbia to be tested. There it is placed in a refrigerator where it can sit for over a month. At some point, a tech will take batches of these samples, give them unique numbers called a TX number (a process called accessioning) and place them in a gas chromatograph mass spectrometer (GCMS) machine to be tested. This should sound very familiar to anyone who watches Abby use this machine on NCIS every week. They claim that they can tell precisely how much alcohol (ethanol) is present in a 100-milliliter sample of urine, and that they are accurate within 0.01 grams. The government wants the court to believe that this is proof beyond a reasonable doubt or your intoxication. There is only problem with this statement in that it couldn’t be further from the truth. The test will show how much alcohol is in your urine, but it can’t show how much alcohol is in your blood. In other words, it can’t tell how intoxicated are. In the next part of this series, we look at why this is the case.
