Dallas, San Antonio, Houston and Austin Offices of the Charles Johnson Law Firm
Charles Johnson Law Firm
Charles Johnson Law Firm Home See Our Case Results About Us Resources Contact Us Dallas Criminal Lawyer Blog
Call now

Blood Alcohol Testing

Blood Alcohol Testing

When an individual is suspected of driving under the influence, law enforcement officials will test his/her blood alcohol content (BAC) to see if it exceeds the 0.08% legal limit. After conducting these tests, if the driver’s BAC is higher than 0.08%, then he/she will be arrested and charged with DWI. There are three main ways to test a driver’s BAC level: a blood test, a breathalyzer test, or a urine test.

Breathalyzer Tests

Breathalyzer machines are the most common modality for testing a driver’s BAC level. In Texas, most law enforcement officers use a device called the Intoxilyzer 5000. When the driver blows into the machine, the Intoxilyzer measures the concentration of alcohol found within the driver’s deep lung region, also called the “alveoli.” It is believed that the concentration of alcohol found in the lung region correlates to the amount of alcohol found in the blood.

However, the Intoxilyzer 5000 and other breathalyzer machines can only estimate a driver’s BAC level, and are subject to error. There are many reasons why an Intoxilyzer 5000 may give inaccurate readings, including:

  • Machine malfunctions
  • Radio frequency interference
  • Improper use
  • Unqualified or inexperienced use of the machine
  • Mouth alcohol contamination
  • Body temperature inaccuracies

Blood Tests

Another way to test a driver’s BAC is to conduct a blood test. Blood tests are much more accurate than breathalyzer tests.  In order to conduct a blood test, the driver is taken to the police station where a trained technician will administer the test. The technician will analyze driver’s blood in a laboratory to determine if BAC levels are higher than 0.08%.

Because blood tests are more accurate than breathalyzer tests, people who believe they were not drunk at the time they were arrested, prefer to take a blood test. However, because blood tests are more accurate, it is harder to challenge them if the results show BAC was higher than 0.08%.

Urine Tests

Urine tests are commonly used to determine if an individual was driving under the influence of drugs. If a police officer suspects an individual is driving under the influence of drugs, he/she will be escorted back to the police station where they must urinate in a plastic cup to be analyzed by a trained technician. Like blood tests, urine tests are much harder to challenge in court because they are extremely accurate at detecting the presence of drugs or alcohol in the body.

Dallas DWI Defense: The Charles Johnson Law Firm

If you were given a blood, urine, or breathalyzer test and then consequently arrested on DWI charges, it is important to contact the Charles Johnson Law Firm immediately. We personally investigate the circumstances surrounding your case to make sure the tests were administered properly, that the equipment was functioning correctly, and that law enforcement did not violate your rights. In addition, we provide each client with aggressive representation, viable options, and compassionate legal care. We do not stop working until we obtain a favorable result, and see that justice has been served.

We can be reached 24 hours a day, 7 days a week.
Call us at 214-234-0111 or toll free at 877-308-0100.
Major Credit Cards Accepted.

Dallas Office - Charles Johnson Law Firm San Antonio Office - Charles Johnson Law Firm Houston Office - Charles Johnson Law Firm Austin Office - Charles Johnson Law Firm