Roland X. Tiemann - Experienced, Affordable, Aggressive, Dedicated, Northern California DUI Defense Lawyer

Breath Defenses

Was Your Breath Test Accurate

You can’t trust the government’s scientific evidence. In many cases the amount of alcohol you consumed would not generate a BAC as high as the government claims. For instance, if you drank three 4 oz glasses of wine or three 12 oz beers, or three 1 oz shots over 2 hours and the cop tells you your BAC is 0.14, that is scientifically impossible and you are being wrongfully accused. Locate your body weight and the number of drinks you drank total. This is your total BAC if you drank those drinks in 1 hour. Subtract 0.015 for every hour it took to consume your number of drinks.

For example:
150 lb person drinks 3 beers in 1 hour = 0.08 BAC
150 lb person drinks 3 beers in 2 hour = 0.65 BAC (0.08 – 0.015 for 2nd hour)
150 lb person drinks 3 beers in 3 hour = 0.50 BAC (0.065 – 0.015 for 3rd hour)

These are rough estimates with many factors that influence the results. But if your estimated BAC is lower than the government’s breath test result, there is a problem with the government’s case.

Blood-Breath Partition Ratio Is Inaccurate Based on Individual Differences

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The biggest problem with breath testing and which leads to the most wrongful convictions is the partition ratio error associated with breath testing. DUI breath testing devices are calibrated to assume that that the “breath alcohol” measured by the breath device accurately reflects the amount of alcohol in the blood based on a 2100-to-1 blood to breath ratio. The Blood Breath Partition Ratio assumes that 2100mL of breath contains the same amount of alcohol as 1 mL of blood. Many studies over the years have found a range of partition ratios in the population from about 900 to 3400. Additionally, the partition ratio is constantly changing during the course of drinking and varies up to 10% within the same person. And there’s no way to determine what a given person’s ratio was at the time of the DUI breath test.For every 200 points lower your partition ratio is below 2100 the breath test will read falsely high by about 0.01%. Say you blow and the breath machine reads 0.08%. If your partition ratio was 1300 (not 2100 like the machine assumes) at the time you gave the breath test your true blood alcohol concentration would be 0.05% which is under the legal limit. Most people assume that if you blow over the legal limit your guilty, but as you can see that is not always true.

Breath Machines Don’t Measure Blood Alcohol Concentration

The problem with breath testing is that in most cases it is not very accurate and can result in an innocent person being wrongfully convicted. For instance, a person with a true blood alcohol level of 0.05 which is under the legal limit and is at the level where there is no impairment could blow into a breath machine and blow a 0.10 reading. This falsely high reading occurs because the breath machine measures alcohol from your breath and not your blood. The government uses this breath alcohol reading (BrAC) to prove your blood alcohol concentration (BAC). The problem is scientifically, breath alcohol concentration (BrAC) and blood alcohol concentration (BAC) are not the same thing. The breath machine measures breath alcohol concentration which is the concentration of alcohol contained in the breath not the alcohol concentration in the blood. The only way to determine the blood alcohol concentration in the blood is to withdraw blood and measure the alcohol. Only blood alcohol causes impairment not breath alcohol. Breath alcohol doesn’t do anything to you. The government uses breath testing as an indirect method for testing a person’s blood alcohol concentration. Breath testing is fast, cheap, and easier than blood testing that is why the government likes it; however it isn’t accurate.

Absorption Can Cause False High Results

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Breath alcohol testing while alcohol is still absorbing into your bloodstream results in falsely high BAC readings. During the absorption stagewhich can last three hours or more after you finish drinking, the BAC in arterial blood is as much as 60% higher than the BAC in venous blood. Because the alveolar deep-lung air blown into the breath machine is bathed in arterial blood, not venous blood, a falsely high BAC is generated. Most credible scientists agree that a breath test should not be given while a person is still absorbing alcohol.

Heartburn Can Cause Falsely High Breath Test Readings

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Suffering from Gastroesophageal Reflux Disease (GERD), acid reflux or heartburn can “fool” the DUI breath machines, causing an erroneously high reading. GERD causes alcohol vapors which are located in the stomach to travel back up through the esophagus, throat and mouth. When this happens, the person blows this “mouth alcohol” into the breath machine. The machine then provides a dramatically higher reading than the person’s true BAC. A person with a true BAC of .05 can blow into a breath machine and obtain a reading of 0.20 or higher. Consequently, the person is arrested and charged with a crime when they could in fact be innocent.

Low-Carb Diets Can Cause Falsely High Breath Test Readings

During metabolism a person’s body on a high protein low carbohydrate diet produces compounds called ketones. If a person consumes carbohydrates, as in drinking alcohol, when these ketones are present the body will produce isopropyl alcohol. Since ethanol and isopropyl alcohol are not distinguished by most breath testing machines it can result into a falsely high test result.

Diabetes or Hypoglycemia Can Cause Falsely High Breath Test Readings

If you are hypoglycemic, borderline diabetic or if you have diabetes, then the consumption of alcohol, even in small amounts, will cause your body to convert elevated levels of acetone into isopropyl alcohol.Since ethanol and isopropyl alcohol are not distinguished by most breath testing machines it can result in a falsely high test result.

Abnormal Hematocrit Can Cause Falsely High Breath Test Readings

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The hematocrit represents the fraction of whole blood composed of red cells and is correlated with the aqueous content of blood. The higher the hematocrit, the lower the concentration of water in blood,. The average hematocrit for normal, healthy males is 47%, with a range of 40-54%; for females the average is 42% and the range is 36-47%. Since ethanol dissolves almost entirely in the aqueous component of blood, two individuals with identical actual BAC’s but with different hematocrits would be expected to produce different Breathalyzer results. The person with the higher hematocrit, and therefore lower blood-water content, would necessarily be characterized by a higher concentration of ethanol in the aqueous component of his/her blood and consequently, by a higher Breathalyzer reading. Given that the breath machine is calibrated at a hematocrit count of 45% studies have shown that the normal variation in hematocrit can produce errors in breath test results in the 10 to 14% range.Therefore, a person with a 0.07 BAC will register 0.08% on the breath machine.

Mouth Alcohol Can Produce Falsely High Results

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Ideally, DUI breath testing devices detect alveolar air of the deep lungs, which is loosely correlated with blood alcohol level. But the breath testing machine can be “tricked” by latent alcohol in the mouth often caused by burping, belching, or the recent use of cough syrup, cold medicine, mouthwash or breath spray.When the breath machine detects mouth alcohol rather than deep lung air, it gives readings greatly higher than the true BAC. This becomes a particular problem for people with dentures, denture adhesives, braces, cavities, food impactions, orthodontic work or who have food particles trapped between their teeth. Food particles act like a sponge and trap the alcohol in the mouth. Don’t forget the breath machine measures molecules of alcohol so it doesn’t take much mouth alcohol contamination to produce a falsely high breath test result.

Fail to Observe 15-Minute Observation Period Prior to The Breath Test

California law requires police to watch a DUI suspect continuously for at least 15 minutes prior to administering the breath alcohol test. During that time the office must make sure that the person does not consume anything, burp, belch, hiccup or regurgitate. Any of these may cause alcohol to travel from the stomach to the mouth. Blowing this “mouth alcohol” into the breath machine triggers a falsely high BAC reading.Officers usually don’t follow this required observation procedure because they are doing their paperwork, writing reports, setting up the machine and conversing with their partners. Failure to follow state law casts doubt on the validity of the test result because of the possible contamination of the breath sample.

Breathing PatternsCan Produce Falsely High Results

Remember the harder you blow the higher you go. That is why police tell you to keep blowing because they know it will result in the highest possible result even if is not the most accurate result. A breath sample longer than 10 seconds can generate a significantly higher BAC reading because the machinery is calibrated to test a 10 second sample. If a person holds his or her breath for a short period of time before blowng into the breath device can increase the alcohol content in exhaled air by up to 15%. Additionally, a person who breaths shallow or holds her breath may blow residual mouth alcohol, again producing a higher reading than her true BAC.

Breath Temperature Can Produce Falsely High Results

Breath temperature is critically important in obtaining and accurate breath test result. Most of the machines used in Sacramento, El Dorado and Placer counties don’t have a way of measuring breath temperature so they arbitrarily calibrate the machines to read everyone’s breath temperature as 34C. The first problem is that the average breath temperature for humans is not 34C but 35.7C and varies as much as ± 1°C amongst different individuals. In addition, every person has a normal diurnal (daily) variation of 1°C. Females also have a temperature variation of about 1°C with the menstrual cycle. These temperature variations are normal. In addition, there are factors that can elevate body temperature above the normal range including the flu or physical or emotional trauma. So right off the bat the breath machine reading is about 10% higher than it should be. An elevation in body temperature of 1°C (1.8°F) results in a 7% higher value in the result. Therefore, a person with a body temperature of 100.6°F and with an actual blood alcohol of 0.07 % will register a value of 0.08 % by the breath test. As can be seen from this hypothetical example, a small difference in body temperature can make the difference of guilt or innocence of drunk driving in defendants with a BAC close to the legal limit.

Breath Testing Machines Mistake Other Chemicals for Alcohol

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DUI Breath alcohol testing machines also detect non-alcohol compounds, which they frequently mistake for alcohol. Among the compounds most commonly mistaken for alcohol are methanol, isopropanol, ethylene, toluene, nitrous oxide, diethyl ether, acetonitrile and isopropanol. The presence of any of these compounds in the DUI suspect’s lung tissue will likely cause a false, or falsely high, blood alcohol reading. People frequently ingest these compounds at work or in other environments where the chemicals are present.

Expired Simulator Solution Can Produce Falsely High Results

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The breath test machine uses an external source of alcohol vapor as a way of verifying that the machine is working properly. If this solution is either mixed incorrectly or is out of date, the BAC reading is not reliable and subject to suppression.

These tests can sometimes be challenged on their accuracy for various reasons, including poor maintenance of testing equipment, which must be regularly serviced to maintain their highest degree of accuracy.  If you have been arrested for drunk driving, we can discuss your case and explore available avenues for your defense. 

Contact a Sacramento DUI Defense Lawyer for aggressive and experienced legal counsel and representation after DUI arrest or charges.

For more information call Roland X. Tiemann
at (916) 939-3900 - (530) 621-1800
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©2011 Law Office of Roland X. Tiemann