Margin of Error in a Breathalyzer Test

To this day, breathalyzer results are often relied upon as strong and conclusive evidence that an individual is guilty of drunk driving. Unfortunately, it has slowly become more apparent that these results don’t hold the irrefutability some have claimed. Researchers, scientists, and attorneys have spent years analyzing breathalyzer machines to arrive at similar conclusions: things are not as they seem.

Why are breathalyzers so faulty?

It is helpful to first understand how a breathalyzer machine operates. The suspect blows air into a device, which is then supposed to calculate the amount of alcohol in their system. However, the calculations are based on mere averages and therefore not unique to each test-taker.

The breathalyzer determines a person’s blood alcohol content (BAC) by multiplying the content of alcohol in the air by 2,100. This number is used because the “average” person typically has 1/12100^th the amount of alcohol of an equal gallon of blood when they exhale. Clearly, what is average for one person may be far from correct for another.

Studies have shown that breathalyzer results vary at least 15 percent from the actual BAC. This is a significant deviance that officers fail to take into consideration. Compounding this problem is the fact that at least 23 percent of all tested individuals will get results that are higher than their actual BAC!  

There are also numerous factors that can influence a breath test reading, but are often ignored by law enforcement.

Results can be tainted by any of the following:

• Carbonation
• Body type
• Age
• Fat/muscle content
• Alcohol intolerance
• Food consumption

What officers are taking at face value is clearly far from the truth. Many times, tests are administered improperly and the alleged offender suffers as a result. It is imperative that you retain a lawyer who will challenge your breathalyzer results. Simply sitting back and expecting a breath test to work in your favor rarely bodes well for those facing DUI charges.

The sooner you take action, the higher your chances for a favorable outcome. My firm’s Miami DUI lawyer has more than 30 years of experience and has successfully challenged countless breath test results for his clients. 

Schedule your free consultation by calling Attorney Jonathan Blecher today!

Margin of Error in a Blood Test

 Some drivers assume that a blood draw test will prove that they are not driving drunk; however, this can be a false assumption. There is little room to argue that the blood alcohol instrument (Gas Chromatograph) has a significant error, sufficient to create reasonable doubt that the defendant is guilty.

When it comes to testing for blood alcohol concentration (BAC) in a driver’s system, blood testing is a relatively reliable method. Defendants can still attempt to challenge blood test results, but they should have an understanding of the margin of error in a blood test.

One such claim from defendants is that the blood testing instrument measured and reported something other than ethyl alcohol, in effect artificially increasing the reported BAC. Gas chromatography happens to be the method used by most, if not all labs to test alcohol in the blood, and it is a universally accepted separation science.

With this method, an instrument separates the sample in the column, and measures the amount of the substances it tests; each substance comes out of the column at different, yet specific times. Because this method separates volatile substances such as ethyl alcohol and isopropyl alcohol before the analysis, gas chromatography is highly specific and does not allow the interference of other substances.

Gas chromatography has been proven to differentiate other volatile substances from ethyl alcohol, and this validation has been conducted extensively by the scientific community. Further, the lab that conducted the analysis should be able to provide supporting testimony in court.

In an effort to ensure accuracy when testing a defendant’s blood for alcohol, state labs are in the practice of conducting duplicate tests on DUI blood samples. This methodology analyzes a subject’s blood twice by using separate portions of the sample. Additionally, dual columns are often used, thereby testing each portion of a duplicate twice.

In the scientific and legal communities, dual column gas chromatography is considered the “gold standard” for analyzing a defendant’s blood alcohol.

Arrested for DUI? Contact me today!

If you are facing DUI charges in South Florida, know that you do have options! As a Miami DUI defense attorney, I have defended over 3,000 cases since 1982, and I welcome the opportunity to help you, too.

Not only am I a member of the National College for DUI Defense, but I am a former prosecutor. I understand Florida’s DUI laws inside and out and I know which DUI defenses work, and which ones have less chance for success in court.

Contact my office today to schedule your free case evaluation!