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Blood Test Versus Breath Test

Driving Under the Influence (DUI) is a crime that has major ramifications if convicted. Police who suspect you of DUI may ask you to take a blood test or a breath test (breathalyzer) to see if they can get proof of their suspicion. Police may ask you to take a field sobriety test too although these type of tests are subjective meaning in the opinion of the arresting officer you failed and may not have the same evidentiary weight that a breath test or blood test will have in court.

breathalyzer test

When a person consumes alcohol, the liquid travels through the esophagus on its way to the stomach and small intestine before entering the bloodstream and making its way through the rest of a person’s body. Eventually, the alcohol in the bloodstream will reach the lungs to be expelled from the body in very small amounts whenever a person breathes out.

Depending on the person, the alcohol in the bloodstream can have a variety of impacts, from the loss of mental acuity to the impairment of physical control. If your actions while driving after drinking alcohol attract the attention of law enforcement officers, it’s possible they might request that you submit to some testing to try and confirm you are over the legal limit and are driving impaired. The legal limit is under 0.08 percent for blood alcohol concentration (BAC) in Tennessee.

Field Sobriety Tests

A police officer may ask you to perform some kind of physical test to test things like coordination, balance, mental ability, or vision. These type of test can often be discredited by a defense attorney more easily than breath or blood tests. With all of these type of tests, the problem is the passing or failing of the test is literally subjective to the opinion of the officer. This means the officer is the one deciding at the time of the testing if you are intoxicated. You may in fact be tired or scared or uncoordinated and in the officer’s opinion you are drunk. Your future is at risk based on one officer’s opinion and that is a frightening proposition.

Breath Test

Breath tests make use of a breathalyzer tool to assess the amount of alcohol (BAC) in a person’s bloodstream. The device works a little like a remote thermometer, with the object placed into the mouth. The person only has to blow into a tube and the device can produce readouts of the person’s blood alcohol level.

Generally speaking, law enforcement officials tend to prefer breath tests because the device itself requires very little training and can be easily transported anywhere. It can be administered on site of the traffic stop. Although trained, police officers do not require a license or registration with any agency to use the device, and the device itself does not require a specific environment to be operational. It in theory works in any environment.

But such breath tests are not as reliable as you may think or what the prosecutor may imply. The breathalyzer results can be negatively affected by environmental situations, such as the weather. What you recently ate may alter the results. For example, if a person ate food that was cooked with wine or marinated with beer, it’s possible the breathalyzer might register the alcohol content in that person’s bloodstream. A good defense attorney can show there are problems with the test results and that it can not be relied upon conclusively for a conviction.

Blood Test

Of the two sobriety tests, blood tests tend to produce the more accurate results but even blood tests can be shown to be suspect.

Rather than take a reading from the alcohol vapors in a person’s lungs, a blood test provides a more direct source for determining an individual’s level of alcoholic toxicity. However, the equipment needed to safely extract a blood sample and provide an accurate data result requires a controlled setting for the test, making it unlikely to administered in the field. Blood test can be administered at the jail or possibly at a local hospital.

The blood test results may be challenged for things like the method of extraction, blood sample storage or blood ample analysis.

Let Us Help

David Clarke is an experienced criminal defense attorney and is familiar with defending his clients with care and compassion. He will properly investigate the charges against you and launch a rigorous defense.

To find out more about blood tests and breath tests in the state of Tennessee, contact The Clarke Law Firm today.