DWI Chemical Tests Blood or Breath?

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DWI Breath Tests

Prior to 2015, Texas used the Intoxilyzer 5000, a device that was old, surpassed by competitors, and had issues. Now, (most areas) use the Intoxilyzer 9000 -- which is not much better, except that it's new. The scientific community agrees that blood testing is the most accurate method to determine alcohol content in the body -- but that's not convenient for law enforcement. So, most commonly, breath tests are use. But they have problems, as you can see below.

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Conditions That May Alter DWI Breath Test Results:

• Prescriptions and Medications;
• Body temperatures, Head Trauma or Injury (such as accident);
• Recent Medical Care and Surgery;
• Alcohol consumed, Rate of Consumption;
• Diseases and Medical Conditions;
• Accident with Deployed Air Bag;
• Mouth Alcohol;
• Vomit or Belching with 15-20 minutes of Breath Test;
• Excessive Exhalation into Breath Unit;
• Breath Test Device not Calibrated;
• Breath Test Device problems

DWI Blood Tests

DWI Blood tests can be more reliable, but there are still significant issues outside of a clinical, research setting. First, if a hospital draws the blood, there is a high probability the blood/alcohol result will be elevated. This is due to hospitals using an entirely different procedure to test the blood. We try to exclude hospital drawn blood from the evidence for that reason. Second, there are many ways the blood can become contaminated, either at the draw site, during storage and transport, or at the lab. Lastly, lab tech error can be an issue concerning reliable testing.

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Conditions That May Affect DWI Blood Test Results:

• Sloppy Labwork;
• Improper Blood Draw;
• Improper Equipment (swab, collection tube, etc...);
• Poor Storage of Blood;
• Contamination of Blood after Draw;
• Illegally Obtained Blood;
• Delay in Drawing Blood;
• Hospital Blood Draw (Procedures Improper for Court Use);

Closely Related Offenses

There are several types of DWI in Texas. A First Time DWI is the most common, but if a person has a prior DWI, then the charge is more serious. A DWI Second Offense is a Class A Misdemeanor and carries more severe penalties. Likewise, having two DWI priors means the next arrest will be considered a Felony DWI.

A first time DWI where the person has a breath or blood result .015% or higher, will have the DWI upgraded to a more serious DWI offense, specifically an Enhanced DWI (Class A).

Lastly, if there is no alcohol involved, or a combination of alcohol and a narcotic, then a person could be charged with a Drug DWI. This is true even if a person is taking legal prescriptions.

If you're looking for other offenses that are related to this one, you can see more information below, or click related legal offenses.

License Suspensions based on Breath, Blood, or Refusals

DWI Failure Cases per Trans. Code 524.022 (a) (1-2): Failure means the chemical (breath or blood) test resulted in a alcohol content of .08% or above. This results in a 90 day suspension, if it's a 1st time DWI or if any prior DWIs are more than 10 years in the past. If there are DWI priors within 10 years, the suspension is 1 year. Source.

DWI Refusal Cases per Trans. Code 724.035 (a-b): Refusal means the chemical (breath or blood) test was refused by the driver. This results in a 180 day suspension, if it's a 1st time DWI or if any prior DWIs are more than 10 years in the past. If there are DWI priors within 10 years, the suspension is 2 years. Source.

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