Working to Prevent DUI Convictions Off Inaccurate Evidence

Blood and breath test evidence are two of the cornerstones of most DUI cases prosecuted in Arizona. While it is looked upon as nearly infallible by the courts, good defense lawyers know that there can be all types of issues with its accuracy. If you have been charged with drunk driving based on the results of a blood or breath test, you should contact an attorney immediately.

At the Rosenstein Law Group, we represent clients in all types of DUI/DWI cases throughout the Phoenix area and across Arizona. Attorney Craig Rosenstein is a Board Certified Phoenix DUI attorney — one of only a handful in the entire state. We know how to examine blood and breath evidence and find the flaws that could provide the keys to your freedom.

Understanding the Breath Test

One of the most common ways to measure and assess a subject’s blood alcohol concentration is through the breath test. This is done by the subject giving a sample of their breath into a machine that determines how much alcohol is on their breath. Per Title 13, Arizona Department of Public Safety: R13-10-103, there are very few devices that are permitted to be used and they must meet rigorous standards of performance.

For example, the device must meet a very specific accuracy limit: less than ± 0.005 grams per 210 liters or ± 5 percent. There are also specific devices that have been approved by the Director for use in the field. Those that are listed by the National Highway Traffic Safety Administration on their Conforming Products List of Evidential Breath Alcohol Measurement Devices fall under this category.

Other approved devices and models include:

  • Intoxilyzer Model 5000
  • Intoxilyzer Model 5000EN
  • Intoxilyzer Model 8000
  • RBT AZ (Alco Sensor AZ / RBT AZ)

For a breath test to be properly administered the arresting officer must determine that the subject fits all criteria and is a good candidate; for example, they must be physically and mentally capable of taking the test. While preparing, the officer must observe the subject for at least 20 minutes to ensure that the subject still meets all criteria; this means they cannot be burping, hiccupping, vomiting or otherwise doing something that would affect the integrity and accuracy of the test.

After 20 minutes, should the subject be suitable, the officer may administer the test. Following — at least 5 minutes after the first test, but no more than 10 minutes later — a test must be administered again. The results of the rests must be within .020 BAC of each other to be considered accurate; if not, results are considered to be “out of range.”

Although considered to be one of the most accurate ways of testing a subject’s blood alcohol concentration, there are many problems that have been noted with the test. For example, the machines are notorious for being delicate and requiring almost constant calibration. If they are not receiving this, there is no way to know for sure that they are still operating correctly. Law dictates how long a machine can go between calibrations; however, if the machine went too long, the results would need to be thrown out. Similarly, there are other extenuating circumstances that can affect validity; if the subject was throwing up, still had alcohol present in their mouth, was a diabetic or other, it could potentially affect the accuracy of the test.

What is Blood Alcohol Content?

Persons who are pulled over and subsequently arrested on suspicion of DUI in the state of Arizona need to be very familiar with the state’s BAC laws. An individual’s blood alcohol concentration is the most frequently used metric of alcohol intoxication, thus making it a widely recognized method of testing among both legal and medical professionals alike. Accordingly, DUI defendants need to be equally as familiar with the different methods of testing BAC in order to effectively fight their charges in court.

The Progressive Effects of Alcohol on Your BAC

Typically, persons who are found to be driving with a BAC of .08 percent or higher are said to be driving under the influence, and can be arrested as such. There are cases, however, in which persons with a BAC level below the standard .08 percent can still be arrested for intoxicated driving. Generally, a person’s level of impairment from alcohol will progress as follows:

  • .010-.029: Very subtle effects on impairment that can only be detected through special methods of testing
  • .030-.059: Effects on concentration
  • .06-.09: Impairment of a person’s depth perception, reasoning, peripheral vision and glare recovery
  • .10-.19: Impairment of a person’s reflexes, gross motor control and reaction time; additional symptoms at these stages include slurred speech, staggering, temporary erectile dysfunction and the possibility of temporary alcohol poisoning
  • .20-.29: Severe motor impairment at this stage, including possible loss of consciousness and memory blackout
  • .30-.39: Impairment of a person’s bladder function, heart rate and breathing patterns; disequilibrium may also be experienced at this time
  • .40-.50: Impairment of a person’s breathing and heart rate; risk of positional alcohol nystagmus
  • >.50: High risk of alcohol poisoning and possible death

Challenging Your Charges

One of the most crucial components involved in challenging the DUI charges that have been made against you is that of your BAC level. Specifically, how your BAC level was determined. Currently, many different methods of measuring a person’s BAC level exist; however, none of these have been proven to yield results that can be relied upon as 100 percent accurate. Most frequently, a person who is suspected of driving under the influence will be tested in one of the following five ways:

  1. Urine sample
  2. Saliva sample
  3. Hair follicle sample
  4. Blood test
  5. Breath test

Most often, however, law enforcement officers will utilize one of the last two methods – blood or breath testing – to secure the results they need to make an arrest. Furthermore, because blood tests are considered to be a highly invasive method, the breath test is much more heavily used. This is a fact that can often be used to the DUI defendant’s advantage, because breath tests are known to produce results that are less than accurate.

In a court of law, the breathalyzer test is recognized as an acceptable method of gathering evidence in a DUI case. When doing so, however, the fact that breathalyzer tests can yield results that vary by up to 15 percent from a person’s actual BAC level must be taken into consideration. In fact, this is such a common problem that some courts have actually thrown out the results yielded by a breathalyzer test, questioning the reliability of such machines.

Blood Test Evidence

Another common form of testing a subject’s blood alcohol concentration is the blood test. This is generally viewed as more scientific and accurate than the breath test, but still, there are noted discrepancies. Unlike breath tests, the blood test cannot be performed roadside; instead, the subject must be taken to an approved facility where the blood will be drawn by a properly trained technician. While this appears to be relatively straightforward, there are still circumstances that can affect the test.

For example, should the technician drawing the blood use an expired NIK kit, the entire test would be false. Similarly, if the technician swabs the draw spot with a solution that contains alcohol, it would affect the alcohol detected in the sample and therefore the entire result of the test. Similarly, during storage, the blood is to be mixed with anticoagulants and preservatives; if this mixture is off or if the proper amount is not mixed in, the blood could essentially go “bad.” Other situations that can occur include the lab technicians mixing in too much salt, or the test being done on the blood serum or plasma instead of the whole blood.

Do You Need a DUI Lawyer In Phoenix?

At the Rosenstein Law Group, we are an experienced DUI defense law firm. Phoenix DUI attorneys from our firm will be able to provide you with skillful and aggressive representation of your case in court if you choose to work with us. There are many serious penalties that you could face for conviction of a DUI charge, do not hesitate to contact our firm today to discuss your case and how our firm will be able to help you.

From offices in Phoenix, Scottsdale and other cities, we represent clients throughout Arizona. Call us at (480) 452-1028 to discuss your case with an experienced DUI attorney.


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