Challenging GC-MS Machine Errors in Arizona DUI Blood Tests
When you are arrested for a DUI in Phoenix, the state often relies on a lab test called Gas Chromatography-Mass Spectrometry (GC-MS) to determine your Blood Alcohol Content (BAC). Prosecutors treat these machine results as absolute facts. However, after more than 42 years of criminal defense practice, I know that these machines are only as reliable as the humans who run and maintain them.
How Machine Contamination Ruins Blood Results
GC-MS machines are highly sensitive instruments that analyze multiple blood samples in a row. To work correctly, the machine must be thoroughly cleaned and calibrated between every single test.
If a lab technician rushes the process or fails to follow strict protocol, a serious error called carryover contamination occurs. This happens when leftover chemicals from a previous person's high-BAC blood sample stick inside the machine's tubes. When your blood is tested next, those leftover chemicals mix with your sample. This mechanical mistake can artificially inflate your BAC reading, making you look guilty when you were actually under the legal limit.
How We Expose Lab Mistakes in Court
We do not just accept the single number printed on the police report. Our defense team demands the raw data logs directly from the crime laboratory. We meticulously audit the machine's history, looking for:
- Signs of chemical carryover from previous samples.
- Missed or failed machine calibrations.
- Inadequate cleaning steps by the technician.
- Software glitches or temperature shifts during your specific testing run.
If the machine was not maintained perfectly, the scientific foundation of the state's case crumbles. We can use these lab errors to argue that your blood test results are completely unreliable and should not be allowed as evidence in court.
Facing DUI Charges in Arizona? Put 42 Years of Experience on Your Side.
Do not let a flawed machine reading decide your future. Contact Brian DiPietro Law, PLLC today at 623-242-2655 or fill out our online form to schedule your free confidential consultation regarding your case.
Do not let a flawed machine reading decide your future. Contact Brian DiPietro Law, PLLC today at 623-242-2655 or fill out our online form to schedule your free confidential consultation regarding your case.
