Draeger Breath Machine a "Flawed Device," Says Report

Posted Friday, May 11, 2018 by Andrew Charles Huff

The State of Washington, like most other states uses a breath test machine to determine whether a person has exceeded the legal blood-alcohol limit of .08 within two hours of driving. For years, the state used what is called the DataMaster Breath Machine.

However, approximately ten years ago Washington state requested bids to replace its aging breath machines, and the only bidder was Draeger, a German medical technology maker. Draeger was then awarded the contract to sell its flagship device, the Alcotest 9510, across the state.

But many of us on the defense side believe this device is faulty. And a preliminary report drafted by two experts have found flaws capable of producing incorrect breath test results. This has led to the current challenge that we are mounting against what appears to be a flawed machine that can affect the results and call into question its accuracy.

The Alcotest 9510 uses two sensors to measure alcohol content in a breath sample: An infrared beam that measures how much light goes through the breath, and a fuel cell that measures the electrical current of the sample. The results should be about the same and within a small margin of error – usually within a thousandth of a decimal point. If the results are too far apart, the test will be rejected.

However, the report found that under some conditions the breath machine can return an inflated reading – a result that could also push a person over the legal limit. One reason is the apparent lack of adjustment made by the machine of a person’s breath temperature. Breath temperature can fluctuate throughout the day, but can also wildly change the results of an alcohol breath test. Without correction, a single digit over a normal breath temperature of 34 degrees centigrade can inflate the results by six percent – enough to push a person over the limit.

The quadratic formula set by the Washington State Patrol should correct the breath temperature to prevent false results. The quadratic formula corrects warmer breath downward but the code doesn’t explain how the corrections are made and the corrections “may be insufficient” if the formula is faulty.

More commentary to follow on the Draeger Alcotest 9510.