If you are being investigated for a DWI, the officer is required by law to ask you if you would like to provide a breath or blood sample. At the point in time the officer asks you this question, you are already under arrest. I have never come accross a case where the officer admits he was wrong after a person gave a breath sample that was under the limit. While I believe there are some officers who would approach the situation this way, my experience has been that the officer will claim either the machine is broken or that you were intoxicated from other drugs and not alcohol if the test comes back negative for alcohol.


You always have the right to refuse a breath or blood test. People often ask whether this is a good or bad strategy and it is a complicated question to answer. Whether it is wise to give a test depends on a lot of factors including what and how much you drank, when you drank it, when you last ate, what you ate, your individual metabolism, whether you are male or female, how long since you were driving that the test would be performed, and probably other factors. What you do need to know is that you have the right to refuse such a test.

Sometimes there will be consequences to refusing, and sometimes there will be consequences to submitting to a sample. If you don't give a sample the prosecutor can use that refusal againt you in your trial. If your driver's license is suspended and you refused, the driver's license suspension will be longer than if you had voluntarily given a sample. Lastly, if you refuse a breath or blood test, the officers are allowed to apply for a warrant to get a sample of you blood. we can fight this warrant later in court.

If you give a sample, your license can still be suspsnded if the sample shows your blood alcohol level is above the statutory level of 0.08. This value can sometimes be used against you in court, depending on the maintenance and reliability of the instrument used on that night.


A lot has been made recently about a "No Refusal" policy in Texas. Let's talk about what they mean. Contrary to its name, a no refusal weekend does not actually mean you lose your ability to refuse.

By the time a person is asked whether to take a breath test or blood test, they are already under arrest. The first words of the warning that are required to be read at that point are "YOU ARE UNDER ARREST FOR [DWI]."

While there can be driver's license complications for refusing a test, you always have the right to refuse to provide either a breath or a blood sample. The state then has the option to go get a warrant, which I can attack later in court. A no refusal weekend simply means that when a person refuses a breath or blood test, the officer is going to go to a judge and ask for a warrant to get a sample of your blood. It does not change your abiliity to refuse a breat or blood test by consent.


Breath Tests

Breath tests in Texas are done on an Intoxilyzer 5000 or 9000 machine. The machine is maintained by a technical supervisor licensed by the Office of the State Scientific Director. The Intoxilizer machines are manufactured by a company called CMI. CMI has had an order against it for over a year to release the technical code for how their machine interprets the data and reduces it to the value reported. As you can imagine, their refusal to give over this information is a critical fact we bring up to attack the breath testing program.

Another critical fact we bring up to attack breath testing in Texas is choices that the Office of the Scientific Director have made. The Intoxilyzer 9000 is programmed to collect a large amount of data during the time a person is giving a sample. Many of these data points were created to ensure that the instrument was working properly on the night in question. Texas, acting through the office of the Scientific director, has asked CMI to turn off a number of these data points being recorded or reported. Think about that. The government who wants you to believe the machine is always working turned off key indicators that the machine might not be working.

One of the experts I hire on a case-by-case basis is a former technical supervisor who left after exposing several scientific weaknesses of the breath testing program. It is important when choosing a lawyer to make sure they understand the science of these machines.

Blood Tests

While Breath testing in DWI cases has been standard for about 40 years or so, Blood testing on DWIs is a somewhat newer phenomenon. As it is newer, each county has a slightly different procedure for how they take a person's blood.

A blood draw can be done either through a person consenting to the draw, or through a warrant. Blood draws should be done by a trained person. That means it ought to be done by either a nurse or a phlebotomist (a trained blood taker). If the officer is the one who took your blood that is something we need to know early in the case.

How the blood was taken from you matters. If the nurse used too small or too big a needle it can change the pressure at which the blood goes into the vial. That pressure, if too high, can crush the red blood cells and elevate the resulting blood alcohol level. If too low, it can cause there to be an insufficient amount of blood to be drawn into the vial. Also if you have bruising around the area where the nurse drew your blood, take photos immediately. This bruising is proof that the blood collected is not from your vein, but from the surrounding muscle. If that happens it can contain chemicals which can elevate your blood alcohol level.

There are so many other areas to question when it comes to the blood draw. Did they use the correct type of vial? Did they correctly invert the vial according to the manufacturer? Was the vial properly stored and refrigerated before it was evaluated? And all of that is before the blood even gets to the lab to be sampled. Trust me when I tell you that this adds several dozen other areas of concern. If your case relies on attacking a blood sample, you should hire a lawyer scientist like RC.

They also have a sample saved so that a lawyer who understands DWI cases can choose to send it to a lab to be re-tested. There are a number of things that can change the integrity of a blood test result, so it's important to pick a lawyer who understands the science of blood testing.

I Am Your Scientific Lawyer

If you have a case involving breath or blood testing, you need a lawyer who understands the limitations of blood tests and the science of a breathalyzer machine. You also need a lawyer who knows how to attack all the different elements of the evidentiary process. Contact my office if you have ANY questions concerning these tests.