In a blood test case, the prosecutor will often present testimony of the senior toxicology analyst at the medical examiner's office and the lab manager in that same office, who performed the laboratory tests on the blood specimen and determined the presence of drugs, a blood THC level, or a blood alcohol concentration (BAC) level.
The toxicology analyst will often testify about their qualifications to conduct the tests and provide testimony about familiar with the protocols involved in administering the tests. The toxicology analyst will often testify about the test methods used were commonly used and accepted within the scientific community.
You also need a DWI defense attorney experienced in fighting to exclude the blood test results from trial and explaining problems with blood testing if the results are admitted at trial.
The criminal defense attorneys at Law Offices of Richard C. McConathy in Fort Worth are experienced in fighting DWI cases involving a blood test. We can help you determine whether the blood test should be excluded because the sample was seized or tested in an unreasonable manner.
We can also help you understand the problems with using blood testing to estimate the alcohol concentration of the sample as an indicator of impairment in a DWI case.
Call our experienced Fort Worth DWI defense attorneys to discuss your pending charges, the potential penalties that apply to that charge, and the most effective ways to fight the case.
Call (817) 422-5350 today.
The criminal defense attorney in a DWI blood test case will often object before and at trial to the admission of the blood evidence because the results lack a sound and reliable foundational basis. Objections to the breath test will often center around a showing that the blood test results were not scientifically reliable or based on sound scientific theory because of problems with the testing methods or the maintanance of the equipment using during the subjects testing.
The defense attorney might also raise objections to the qualifications of the emergency room nurse at the hospital who took the defendant’s blood specimen or show that less than sanitary procedures were used for taking the sample as required by Section 724.017 of the Transportation Code.
The attorney will also make objections to the qualifications of the toxicology analyst to perform the tests and challenge the methods used to conduct the tests or their knowledge of those methods.
In blood test cases, the DWI defense attorney will often argue that the State failed to demonstrate the test results were scientifically reliable or based on sound scientific theory. In order for scientific evidence to be admissible at trial, it must be considered sufficiently reliable as to be of help to a jury. Scientific evidence must typically meet three criteria to be admissible:
In the context of blood test evidence, Section 724.064 of the Texas Transportation Code provides that at the trial of offenses under Chapter 49 of the Penal Code, which includes DWI, “evidence of the alcohol concentration or presence of a controlled substance, drug, dangerous drug, or other substance as shown by analysis of a specimen of the person's blood, breath, or urine or any other bodily substance taken at the request or order of a peace officer is admissible.” TEX. TRANSP. CODE ANN. § 724.064..
By enacting Section 724.064, “the Legislature has already determined that the underlying science is valid, and that the technique applying it is valid as long as it is administered by individuals certified by, and using methods approved by the rules of [The Department of Public Safety].” Reynolds v. State, 204 S.W.3d 386, 390 (Tex.Crim.App. 2006). For instance, in Mireles v. Texas Dept. of Pub. Safety, 9 S.W.3d 128, 131-32 (Tex. 1999), the court found that the Texas Legislature has statutorily recognized the scientific theory and technique behind chemical tests of the breath or blood.
As a result blood specimen test results are admissible even without proof that the underlying scientific theory is reliable. Garcia v. State, 112 S.W.3d 839, 848 (Tex.App.–Houston [14th Dist.] 2003, no pet.). Nevertheless, in a DWI blood test case, the State must show that the blood specimen was taken by a qualified person, such as a “registered professional nurse” or a “licensed vocational nurse.”
The prosecutor with the District Attorney's Office must also show that the blood sample was taken in a “sanitary place.” TEX. TRANSP. CODE ANN. § 724.017. The courts have also found that for evidence of blood-alcohol concentration to be admissible, there must be evidence showing compliance with the requirements of Section 724.017.
Also, in order to meet the requirements of Rule 702 of the Texas Rules of Evidence, the State must demonstrate that “the specimen was taken and analyzed by individuals who are certified by, and were using methods approved by the rules of [the Department of Public Safety]” and that the technique was properly applied in accordance with the department's rules on the occasion in question. Reynolds, 204 S.W.3d at 390-91.
These requirements for blood testing in Texas may be met by evidence that the person who performed the test “knows the protocol involved in administering the test and can testify that he followed it on the occasion in question, [but] he need not also demonstrate any personal familiarity with the underlying science and technology.” Id. at 391.
Even if the DWI blood test results showing an alcohol concentration are admitted, your criminal defense attorney can show problems with the way the sample was taken, stored, and tested.
The criminal defense attorney's main priority in these cases is finding a way to get the legal or medical blood test results excluded from evidence. For DWI cases in Texas, the most common attacks against the blood evidence can include:
In a DWI case, the prosecutor will often use blood test documents to seek the admission of the results of blood alcohol concentration testing at trial. Your attorney can also inspect the evidence and learn more about how it was drawn, analyzed and stored.
Before any hearing or trial, your criminal defense attorney will carefully review all documents related to blood testing including:
The following "blood withdraw procedure form" is used in Texas DWI Blood Test cases.
The form is signed by both the arresting officer and the nurse or medical technician, the time of the blood draw, and the suspect's name and the offense number.