An arrest for driving under the influence (DUI) will include some sort of biological findings to prove that the subject was too intoxicated to drive. However, like all forms of DUI evidence, biological findings are a tricky area for the state to navigate successfully. Read below to find out more about these common DUI biological tests and how they can be invalid.

DUI Evidence in General

Many have seen law enforcement having suspects perform roadside sobriety testing. However, that sort of evidence must be backed up by biological testing to be usable by the state. Other forms of evidence presented by the prosecutor's office are dash cam and body cam footage, as well as the arresting officer's report. None of those secondary forms of evidence can stand alone as biological test results can. That means their accuracy must be unquestionable.

Urine Testing

Though not used as often as other blood and breath testing, some states do provide urine testing as an option. However, there are several issues with urine testing. Firstly, experts are not in agreement on how blood alcohol concentration (BAC) is mathematically determined using urine. There is also the issue of suspects that are unable to produce urine for a test. Then, you have privacy issues for suspects who cannot produce urine due to the circumstances. In most cases, states that have urine testing available as an option use one of the other choices instead. If you were arrested and urine testing was used, experts can be called to challenge the results based on the calculation of the BAC, the sample temperature, and other problems with urine testing for DUI.

Breath Testing

The breathalyzer is a common way to detect alcohol molecules in a subject's expelled breath. The small unit used at the roadside is a portable device and those results must be repeated with the use of a larger breathalyzer unit at the police station. These devices must be used by certified officers only and the machines must show proof of recent recalibration maintenance. Breath testing results can be influenced by the subject's use of mouthwashes, breath fresheners, toothache remedies, medical conditions, and more.

Blood Testing

In most states, blood testing is considered a medical act and may not be performed without the subject's permission or a warrant. However, if the test is performed properly, it's known to be the most accurate form of biological testing for the presence and amount of alcohol. The blood sample must be taken by trained personnel, transported properly, held at a certain temperature, and stored correctly, however.

If you have been arrested for DUI, speak to a DUI attorney about your defense. DUI charges can be beaten, so take action today.