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Causes of False Positive DUI Tests

Posted on December 6, 2023 in DUI,Field Sobriety Tests

The police use various testing methods to determine if someone is driving under the influence (DUI) of drugs or alcohol. Unfortunately for the public, the devices and technology used can be flawed, leading to inaccurate and unreliable test results. At Rosenstein Law Group, we can help you argue against false positive DUI test results.

Improper Device Calibration

The breathalyzer is one of the most common devices used to measure the amount of alcohol in a driver’s blood. It is a diagnostic device that calculates the amount of alcohol in the air that a person breathes. False positives are often linked to breathalyzer tests due to the fact that the breath is an unreliable way to measure blood alcohol concentration (BAC).

One of the many things that can go wrong with a breathalyzer test is improper device calibration. A breathalyzer device must be checked and the sensor must be correctly adjusted to ensure an accurate reading. Without proper calibration, the device will display inaccurate and inconsistent BAC measurements. Over time, improper calibration can damage the device.

Incorrect Test Administration

A DUI test must also be properly administered. An officer who has been specially trained in the use of the equipment must conduct the test. The test must be administered correctly and in accordance with applicable rules and guidelines. Any mistakes made during this process could contribute to a false positive.

Contaminated Results

If an individual eats certain things prior to a breath test, this could affect the results. For example, people on keto or low-carb diet plans may have increased levels of acetone present in the air that they breathe. The breathalyzer test could read acetone as alcohol. Mouth sprays and mouthwash could also alter test results. Finally, contaminants in the environment could infiltrate the test and lead to a false positive.

Lack of Deprivation Period

In Arizona, a police officer is required to adhere to a deprivation or observation period of at least 20 minutes during a DUI stop prior to administering a breath test. During this period, the suspect cannot be permitted to eat, drink or smoke anything. If this deprivation period is not observed, this could place the validity of a positive DUI test result into question.

Medical Conditions and Medications

Certain medical conditions can affect the results of a DUI test. Gastric reflux, for example, can alter the results of a breath test, while diabetes or high blood ketones could affect a blood test. It may also be possible to argue that a suspect had a medical condition that altered the results of a field sobriety test, such as the physical inability to stand on one leg. Finally, ingesting certain medications could alter the results of a BAC test.

Laboratory Error

Poor storage practices at a laboratory could affect the results of a lab analysis of blood and urine samples. Samples that have been stored at the wrong temperature or for a long period of time, for example, may give false positive drug or alcohol test results. Various other human errors in the lab could also generate incorrect results, including cross-contamination and issues with the chain of evidence.

If you have been arrested for a DUI in Arizona, contact Rosenstein Law Group to challenge an inaccurate test result and false positive.

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