What is Chemical Testing for DUI?

Chemical tests, usually breath tests and blood tests, are generally accurate. Perhaps more importantly, the chemical test conviction rate is much higher than the non-test conviction rate. However, no scientific instrument is perfect, and that includes Breathalyzers and blood test analysis tests. More on that below.

These scientific flaws allow a Tampa criminal defense lawyer to cast doubt on the accuracy of chemical test results. If jurors have a reasonable doubt as to the results, the prosecutor must rely on weak circumstantial evidence, mostly from the field sobriety tests. If that happens, and the possibility of a conviction plummets, many prosecutors are willing to make favorable deals, such as a DUI reduction to reckless driving.

Blood Tests

Despite the fact that blood tests are much more accurate than breath tests, most police departments only administer blood tests in limited situations. The Supreme Court recently held that police officers need search warrants to administer these tests. Most police officers aren’t willing to go the extra mile and jump through all the necessary hoops.

Frequently, a Tampa criminal defense lawyer strongly implies that if police didn’t administer an accurate blood test, they either botched the case or had something to hide.

Furthermore, blood tests aren’t 100 percent accurate. Normally, a Tampa criminal defense lawyer partners with a degreed chemist who re-tests the blood sample. Frequently, the results these chemists find are much different from the results police technicians claim they got.

Additionally, blood samples often have chain-of-custody issues. Usually, these samples travel from clinics to laboratories to evidence rooms to courtrooms. Any gap in the chain of custody taints the reliability of the sample.

Breath Tests

Despite all its bells and whistles, the Breathalyzer is simply an updated version of the 1920s Drunk-O-Meter. Like the Breathalyzer, the DOM used breath alcohol levels to estimate blood alcohol content.

That fact erodes jury confidence in Breathalyzers. It also erodes juror confidence in police Breathalyzer techs, who usually go on and on about breath test accuracy rates.

Furthermore, the Breathalyzer, like the DOM before it, has some specific flaws. These problems, which loom large in .09 and other borderline cases, include:

• Improper Calibration: All those bells and whistles on the Breathalyzer mean these gadgets require extensive calibration and maintenance. The state must produce such records at trial. A Massachusetts judge recently threw out thousands of Breathalyzer convictions because the devices weren’t properly calibrated.
• Mouth Alcohol: Police officers usually don’t adhere to the fifteen-minute pre-test monitoring requirement. If the subject belches or vomits during that period, which is likely if the subject was queasy, mouth alcohol particles flood into the mouth and skew the breath test results.
• Unabsorbed Alcohol: When people drink, the liver processes alcohol before it enters the bloodstream. So, if the subject had been drinking in the hour or two prior to the test, that alcohol isn’t yet in the bloodstream, so the BAC estimate is artificially high.

Once again, degreed chemists usually drive home these flaws with jurors. Even a chemistry student usually has more credibility than a police Breathalyzer tech.

Work With a Tough-Minded Hillsborough County Attorney

A criminal charge is not the same thing as a criminal conviction. For a confidential consultation with an experienced criminal defense lawyer in Tampa, contact the OA Law Firm. We routinely handle matters throughout the Sunshine State.

Source:

ncbi.nlm.nih.gov/pmc/articles/PMC2760408/