Freedom through Independence: Erroneous DWI Breath Test Results

Posted On May 06, 2010 by Charles Ramsay

Today we conclude our four part blog series on independent testing and analysis. In parts two and three we discussed how independent analysis of the state's blood and urine samples revealed inaccurate BCA test results. Today our series concludes with our posting of the administration of independent testing. We describe a case litigated last month where our client's independent blood test refuted the state's breath test.


We have revealed numerous problems with Minnesota's Intoxilyzer 5000 breath test machine in this blog and elsewhere. Yet the BCA continues to claim the breath test machine yields accurate, valid and reliable results. With a little foresight, leading to the administration of an independent blood test, we are able to demonstrate the inaccurate breath test results.

The Intoxilyzer 5000 is designed to retain a portion of the breath sample collected in an apparatus called a "tox trap|, a silicon device that attaches to a connection on the back of Intoxilyzer. After a subject has supplied a breath sample, the machine blows the sample out an ejection port, to which the the tox trap is affixed. The operator then seals the tox trap, keeping the air within the tox trap so that it can be independently analyzed in the future.

Although Minnesota breath test machines have this capability, the Minnesota Bureau of Criminal Apprehension (BCA) decided against using a tox trap to preserve breath samples. As a result, we are unable to obtain an independent analysis of a subject's breath as we are able to do with blood and urine samples.

We don't let the BCA's decision to discard critical evidence prevent us from fully representing our clients. While we can't independently analyze a breath sample, we are able to obtain an independently collected sample under Minn. Stat. sec. 169A.51, subd 7 (b). The statute states:

The person tested has the right to have someone of the person's own choosing administer a chemical test or tests in addition to any administered at the direction of a peace officer; provided, that the additional test sample on behalf of the person is obtained at the place where the person is in custody, after the test administered at the direction of a peace officer, and at no expense to the state.

Mark's DWI Breath Test Case & Independent Blood Test

In a case I litigated last month, we introduced the results of my client's independent blood test to demonstrate the breath test results were inaccurate. My client was arrested for DWI. He had called me before giving a breath test. During the |midnight call| I arranged for him to obtain an independent blood test. Mark submitted to the breath test which showed his alcohol concentration was .11, well above the legal limit. His independent blood test, administered two hours and 20 minutes later was .04.

The two test results cannot be reconciled.

The average burn off rate recognized by forensic scientist (including the Minnesota Bureau of Criminal Apprehension) is .015/hour. Multiplying .015 by 2 1/3, we had a total |burn off| of .035 during the time between the breath test and the blood test. Subtracting the burn off of .035 from .11, the breath test result should have been .075 at the time the blood was drawn â?? under the legal limit! The breath test result was very inaccurate.

Conversely, if we were to add the total burn off of .035 to the .04 blood test result, we would see that my client's actual alcohol concentration by blood at the time of the administration of the breath test was .075!

We are well aware of Minnesota's Intoxilyzer 5000 software problems. The problems deal with sampling, volume measurement and specificity. The BCA continues to insist the test is accurate. This demonstrates the Intoxilyzer 5000's problems are well beyond source code issues, it does not provide accurate test results. Only by obtaining an independent blood test were we able to prove the breath test inaccurate.

Part 1: Freedom through Independence: Crises in Our Nation's Forensic Science System

Part 2: Freedom through Independence: Erroneous DWI Blood Test Results

Part 3: Freedom through Independence: Erroneous DWI Urine Test Results

Part 4: Freedom through Independence: Erroneous DWI Intoxilyzer 5000 Breath Test Results