It is sometimes believed in Houston that failing a blood-alcohol test results in an automatic DWI conviction. That is not the case. There are many factors involved with a blood-alcohol test being accepted as evidence in a Harris County court. In this post, The Haggard Law Firm will discuss some of the legal issues surrounding these tests as well as various ways we fight against the results for our clients. If you or a loved one has been charged with a DWI and possibly even taken a blood-alcohol test, contact us today for a free consultation to explore options for fighting against a conviction.

Suppression of blood results

One defense to a failed blood test is the method of analysis used to analyze the sample. Most DWI blood vials are analyzed at a police forensic lab using the forensically-approved gas chromatography method. But sometimes clients’ blood is drawn at a hospital ER. If the hospital draws blood as a part of your medical care, and not at the request of police, the DA’s will issue a Grand Jury Subpoena for those results, which will show us what method was used, which for hospitals is usually the enzymatic assay method. This is not a reliable method for analyzing blood alcohol content and is likely to yield false results. If this is the method used to analyze your blood, we will file a Motion to Suppress. The only way for the State to prevail on this is if they can prove that enzymatic assay is a valid forensic method – which will be next to impossible for them.

Typically we see hospital blood draws done after serious accidents. Suppose you are unconscious after an accident and taken to a hospital. That hospital will draw blood as a precaution before administering any medications. Then if you later get charged with an alcohol-related case, as often happens, the medical records will show that the hospital used the non-forensic analytical method of enzymatic assay, which will be grounds for a suppression.

No consent, no warrant, non-sanitary location

If law enforcement requests the blood to be drawn the arrested person must give their consent or (unless exigent conditions can be proved) police must obtain a warrant. Further, the draw must be done by a qualified technician in a sanitary location – the police station, when the blood draw is done there, becomes a de facto hospital ER room and contamination in the area where the blood draw is done, or in the various instruments used in the draw, is a breach of protocols. If any of those conditions are not met, we may be able to get the results suppressed pre-trial.

Failure to follow protocols

Further, to protect the integrity of the sample and the chain of custody, the police officer who ordered the blood sample to be taken must observe the blood draw and then must take the vial into his custody immediately after the blood is drawn. Other failures will also be grounds for suppression: Improper technique used to cleanse the site; improper technique used in the blood draw; use of expired solutions and materials, and other mishandling of the evidence.

Analyst must testify at trial

If we fail to get the results suppressed pre-trial and the case reaches trial, the State must produce the actual blood sample analyst for cross-examination. Sometimes prosecutors will try to use testimony from someone else to get around having to use the actual analyst in trial. However, there is too much involved with the procedures surrounding the draw, the analysis, the equipment maintenance, the interpretation of the results, etc. for us to let the State get away with using anyone at trial except the actual technician who prepared the sample for testing. If the actual analyst is not made available for cross-examination we can suppress the blood results as being not admissible.

Failure to take medical history

We have also had clients who have various medical conditions that precluded having blood drawn. If the technician drawing the blood did not first take a brief medical history of the client to determine if there are any contra-indications to a blood draw then we may be able to use this failure as grounds for suppression.

Hire an Experienced DWI Defense Attorney

Even if you have failed a blood-alcohol test, we can fight for you! Carl Haggard has over 30 years of verified winning experience defending people against DWI / DUI charges in Houston and Harris County. He offers a free confidential consultation about your case and then will go to work for you to provide the best defense possible against your charges.

Harris County DWI Attorney