The testing of breath is the most common method used by law enforcement of testing blood-alcohol levels. There is persistent debate over whether this method is reliable. (Blood tests are the most reliable method.) While courts have accepted breath analysis results as an admissible form of evidence (when performed properly), there are many who strongly feel that courts should not rely on these results as they are often inaccurate.
Given the potential problems involved with the reliability of breathalyzer results, you may wonder why they are so frequently used. First, they are the most convenient and economical method for law enforcement to use. Second, it is the least invasive and embarrassing way for the arrestee.
There are several machines used by law enforcement today. The most popular machine is the Intoxilyzer model 5000 which is the device used by the Broward Sheriff’s Office in seeking DUI convictions. The Law Offices of William Moore privately owns an Intoxilyzer 5000 and uses the device to demonstrate to clients how it can malfunction. Many are surprised even at the appearance of this “so called” instrument and their faith in the machine’s ability to convict them is lessened when the machine is dismantled in order to reveal an ancient microprocessor which was first introduced in 1975.
The Intoxilyzer 500 relies on an “infrared spectroscopic analysis”. This means, that alcohol vapor captured in a chamber will absorb light waves of a certain frequency when beamed through it. The more alcohol present in the chamber (i.e. the higher the percentage of alcohol in the breath sample) the more light is absorbed. Basically, this method determines the level of alcohol concentration by measuring the amount of light that reaches a receptor at the end of the chamber. The more light – the lower the level of alcohol in the breath. The problems associated with the use of light to determine blood alcohol include but are not limited to the following:
Most Breath Fresheners contain alcohol that can be trapped in the mouth and then blown directly into the chamber of the intoxilyzer. This alcohol is unabsorbed and can magnify the results many times.
Most breath machines will register different chemicals (such as acetone) found in your mouth and in your breath as alcohol. These substances are referred to as “interferents” and can be produced by those who regularly work around industrial compounds or even by someone’s being on a diet. The National Highway Traffic Safety Administration has even gone as far as to produce a report on this subject entitled The Likelihood of Acetone Interference in Blood Alcohol Measurement.
Interference with the police radio can result in inaccurate readings according to a study conducted by Smith & Wesson who is a major manufacturer of breatholyzers.
Testing during the “absorptive” phase:
Test results may not be reliable if you are not done absorbing alcohol. If you had a drink before hitting the road or still have food in your stomach, that can affect your result.
Acid Reflux Disease
People who regurgitate due to a medical condition such as acid reflux disease will magnify the results of breathalyzer readings to a great extent upon providing a breath sample. Many persons tested who have had only one drink have tested over the legal limit. Often, in such cases, the individual was not even aware of the medical condition leading to this result. Consequently, it is incumbent on a qualified attorney to have their clients adequately diagnosed for the existence of medical factors that may have caused incorrect breath results.
Weight and Breathing Pattern of the Test Subject
Studies of the Intoxilyzer 5000 have routinely shown that a persons weight and breathing pattern can have significant effects on the results produced by the device.
The attacking of the Intoxilyzer 5000 begins with first obtaining and then carefully scrutinizing maintenance records of the machine for months prior to in even becoming involved in your arrest. The conditions in which the machine was used in your DUI investigation in addition to the credentials and licensing of the breath test operator and technician must be adequately reviewed as well.
For a more detailed discussion about attacking the results of your breath test, please contact our office so that I may more fully explain the weaknesses associated with this fragile law enforcement device. In the mean time, consider the following detailed account of problems associated with the Intoxilyzer 5000, as reported by Wikipedia, the free online encyclopedia:
A major problem with some machines is that they not only identify the ethyl alcohol (or ethanol) found in alcohol beverages, but also other substances similar in molecular structure. Those machines identify any compound containing the methyl group structure. Over one hundred compounds can be found in the human breath at any one time and 70 to 80 percent of them contain methyl group structure and will be incorrectly detected as ethyl alcohol. Importantly, the more different ethyl group substances the machine detects, the higher the false BAC estimate will be.
The National Highway Traffic Safety Administration (NHTSA) has found that dieters and diabetics can have acetone levels hundreds and even thousand of times higher than those in others. Acetone is one of the many substances that can be falsely identified as ethyl alcohol by some breath machines.
Substances in the environment can also lead to false BAC readings. For example, an alcohol-free subject was asked to apply a pint of contact cement to a piece of plywood and then to apply a gallon of oil-base paint to a wall. The total activity lasted about an hour. Twenty minutes later the subject was tested on an Intoxilyzer, which registered a BAC of .12 percent. This level is 50% higher than a BAC of .08, which constitutes legal intoxication.
Any number of other products found in the environment can cause erroneous BAC results. These include compounds found in lacquers, paint removers, celluloid, gasoline, and cleaning fluids. Other common things that can cause false BAC levels are alcohol, blood or vomit in the subject's mouth, electrical interference from cell phones and police radios, tobacco smoke, dirt, and moisture.
Breath testers can be very sensitive to temperature and will give false readings if not adjusted or recalibrated to account for ambient or surrounding air temperatures. The temperature of the subject is also very important. Each one Fahrenheit degree of body temperature above normal will cause a substantial elevation (about 8%) in apparent BAC.
Breath testing machines assume a 2100-to-1 ratio in converting alcohol measured in the breath to estimates of alcohol in the blood. However, this "partition ratio" varies from 1300:1 to 3000:1 or more among individuals and within a given individual over time. Assuming a true (and legal) blood-alcohol concentration of .07%, for example, a person with a partition ratio of 1500:1 would have a breath test reading of .10% -- over the legal limit.
Breathing pattern can also significantly affect breath test results. One study found that the BAC readings of subjects decreased 11 to 14% after running up one flight of stairs and 22-25% after doing so twice. Another study found a 15% decrease in BAC readings after vigorous exercise or hyperventilation. Hyperventilation for 20 seconds has been shown to lower the reading by approximately 10%. On the other hand, holding your breath for 30 seconds can increase the breath test result by about 15%.
Some breath analysis machines assume a hematocrit (cell volume of blood) of 47%. However, hematocrit values range from 42 to 52% in men and from 37 to 47% in women. A person with a lower hematocrit will have a falsely high BAC reading.
Failure of law enforcement officers to use the devices properly or of administrators to have the machines properly maintained and re-calibrated as required are additional sources of error.
Research indicates that breath tests can vary at least 15% from actual blood alcohol concentration. An estimated 23% of individuals tested will have a BAC reading higher than their true BAC.
Related Articles & Posts
- Breath Tests in Broward County Called Into Question After Operator Fired
- Fort Lauderdale DUI Attorney on Alcohol Testing Accuracy
- Intoxilyzer 8000
- URBAN MYTHS ABOUT DUI
- DUI and Drugs
- DUI by the Numbers
- Breathalyzer Tests Questioned After Calibration Error, Says Broward DUI Attorney
- Driving Under the Influence & Prescrption Drugs -- Broward DUI Attorney
- Alcohol Absorption
- Blood samples in Broward County DUI arrests
Criminal Defense Hotline: (954) 523-5333
Speak to a veteran 20 year career criminal lawyer from our Law Firm right here in Broward County.
Any Day/Any Hour, No Waiting, No Consultation Fee
Additional crime topics
- DUI Defense
- Finding the "Best DUI Lawyer in Broward County"
- DUI in Florida
- Florida DUI Law
- What are the penalties for a DUI conviction?
- DUI Practice & Procedure
- Where are Florida DUI Checkpoints?
- Florida DUI Facts
- Defending DUI is Complex
- Repeat DUI
- Self-Representation - Public Defenders
- Challenging Breath Test Results
- Our Broward County DUI Defense Book
- Crime of Fraud
- Disorderly Conduct
- Criminal Mischief
- Shoplifting Lawyers
- Common Criminal Charges
- Grand Theft Auto
- Assault and Battery
- Domestic Battery
- Juvenile Delinquency
- Court Hearings & Motions
- Pre-Trial Motions & Criminal Trial
- Pre-Trial Motions Criminal Law Question & Answer by our Fort Lauderdale Lawyers
- After the Arrest
- Setting a Bond Hearing
- Miranda Rights
- The Officer Didn't Read Me My Rights
- How is a Motion to Suppress Used by the Defense?
- Identification Evidence
- Voice Identification
- Fingerprint Evidence
- Double Jeopardy
- Jurisdiction Limitations of Police Officers
- Plea Agreements in Florida
- Plea Deals
- Violation of Probation