Rochester Minnesota DUI Lawyer

Blood Alcohol Testing Attorney Minnesota

There are three main ways by which the police measure the blood alcohol content of a driver suspected of driving while impaired:

• Breath Test
• Blood Draw
• Urine Test

The breath test is the most commonly used one. If for some reason the Intoxylizer, the machine that measures the blood alcohol content through the breath, is not working, a driver has a choice between the blood draw and the urine test. Additionally, as long as you agree to submit to testing of your blood alcohol content, you are entitled to an additional test of your choosing, at your expense.

The blood test is the most accurate of the three and is often used in cases of criminal vehicular operation. The urine test is the least reliable of the three.

If you have questions about blood alcohol testing in Minnesota, please contact our Rochester Minnesota DUI attorney, to see how we can help.

Breath Test - Intoxilyzer

The State of Minnesota currently uses the Intoxilyzer 5000 machine to test blood alcohol concentration. The Intoxylizer is an infrared breath alcohol machine. Its basic design revolves around the principle that certain molecules absorb light at a certain wavelength. Accordingly, compounds can be identified by the different wavelengths at which they absorb light. However, many compounds will absorb the energy of any one particular wavelength, which means that the machine does not necessarily identify a particular compound, but rather narrows the number of compounds a molecule can be.

As required by Minnesota statutes, in each use, the Intoxilyzer performs two separate tests and also runs a control test of a solution with a known alcohol concentration. Within each test, the machine must generate two alcohol concentration results. These results must be within 0.02% of each other. Additionally the control test must be within 0.02% of the known alcohol concentration.  

The proper operation of the Intoxilyzer 5000 can be easily thrown off by several factors, such as radio frequency interference (RFI). That is why most Intoxilyzers are located within a detention center. Additionally, mouth alcohol will also artificially elevate a test result and make a subject appear to have a much higher alcohol concentration than that which is actually present in the blood or deep lung air. Mouth alcohol is usually the result of burping or belching. If that occurs, that the test cannot be accurate until 15-20 minutes have passed.

Blood Draws

Blood and urine samples are analyzed by gas chromatography. As noted above, the blood test is the most accurate of the three available. However, it is also the most invasive. It usually requires trained personnel sticking a needle into your vein to obtain the draw.

In a concept similar to the Intoxilyzer, gas chromatography works on the principle that different compounds travel at different speeds. The basic setup is a cylindrical tube through which a stream of gas is passed continuously. When the blood is analyzed, the different compounds within it will travel at different speeds. Those measurements are taken and will determine the alcohol concentration in the blood. 

Urine Test

When a person consumes alcohol, it will enter the blood stream through the intestines within a matter of minutes. That is why a blood test accurately measures the alcohol concentration at the time of the draw. However, it takes alcohol significantly longer to be metabolized by the body and end up in the urine. Therefore, a urine test may not accurately measure the blood alcohol content at the time of the test, but rather that of 60-90 minutes prior. Additionally, the alcohol content in the urine may vary significantly based on the person’s metabolism and their level of hydration.

The best procedure would be to allow the person that is giving a urine sample to void the bladder once, and then provide a second sample for the test. However, this procedure is not followed every time. That is one reason urine tests are less reliable than the other available tests.

Contact Us Today For a Free Consultation

If you have additional questions about blood alcohol testing in Minnesota, please contact the Dilaveri Law Firm today. We always offer free initial consultations to our client. Call 507.206.6020 or complete our free case evaluation form.