Can Someone Challenge the Results of a Blood Test?
Answer:
Yes — a blood test result in a Georgia DUI case is not the final word. Blood test evidence can be attacked from multiple angles, and in many cases those challenges succeed in suppressing the result entirely or undermining its reliability at trial. Defense counsel can challenge how the blood was obtained, including whether law enforcement had probable cause, whether a search warrant was required and obtained, whether Georgia’s implied consent notice was properly administered, and whether any consent was truly voluntary. Even when the draw was lawful, the integrity of the sample during handling, transport, and storage can be challenged — blood samples not refrigerated or improperly sealed can degrade and ferment, artificially elevating BAC readings. The GBI Crime Lab analysis itself, including equipment calibration records and protocol compliance, can also be scrutinized for error.
Yes — a blood test result in a DUI case is not the final word, and challenging it is one of the most important components of an effective DUI defense strategy in Georgia. Blood test evidence can be attacked from multiple angles, and in many cases those challenges succeed in suppressing the result or undermining its reliability at trial.
How Blood Testing Works in Georgia DUI Cases
In Georgia, nearly all blood test analysis in DUI cases is performed by the Georgia Bureau of Investigation (GBI) Crime Lab. When a law enforcement officer draws or arranges for the drawing of a blood sample, that sample is typically packaged and sent to the GBI through the mail. This is not a trivial detail — it means the sample may sit in transit for days, potentially without refrigeration, before it ever reaches the lab. Once received, it is logged, stored, and eventually analyzed by a GBI technician using specialized equipment.
Each step in that chain — from the blood draw to mailing to receipt to storage to analysis — represents a potential point of failure that a defense attorney should scrutinize.
Challenging How the Government Obtained Your Blood
The most common and often most effective avenue of attack in blood test cases is not the lab result itself — it is the manner in which the blood was obtained in the first place. Georgia and federal constitutional law impose strict requirements on law enforcement before a blood draw can be legally conducted. If those requirements were not met, the results may be suppressed entirely, meaning the jury would never see them.
Common grounds for challenging the blood draw include the following. First, the officer may have lacked probable cause to arrest you for DUI in the first place, which means everything that followed — including the blood draw — may be constitutionally tainted. Second, in many cases, law enforcement is required to obtain a search warrant before drawing blood; if they did so without one and without a recognized exception to the warrant requirement, the evidence may be suppressed. Third, Georgia’s implied consent law requires that officers read a specific notice to the driver before requesting a blood sample; an improper or incomplete reading of that notice can render the blood draw invalid. Fourth, if a blood draw was conducted based on the driver’s purported consent must have been given freely and voluntarily — consent obtained through coercion, confusion, or improper pressure may be challenged.
Challenging the Integrity and Handling of the Sample
Even when the blood draw itself was lawfully conducted, defense counsel can examine whether the sample was properly handled, stored, and transported. Blood samples that are not refrigerated, that are improperly sealed, or that sit in transit for extended periods are susceptible to degradation and fermentation — processes that can artificially elevate BAC readings. Chain of custody issues — gaps or irregularities in the documented handling of the sample from collection to analysis — can also raise legitimate questions about whether the sample tested was the one taken from the defendant.
Challenging the Lab Analysis Itself
The GBI’s analytical equipment, while sophisticated, is not infallible. Defense counsel can request records related to the maintenance, calibration, and quality control of the instruments used to analyze the sample. Documented equipment issues, deviations from established protocols, or analyst error can all provide grounds to challenge the reliability of the reported result.
A blood test result may feel like overwhelming evidence, but it is rarely the end of the analysis. An experienced DUI defense attorney will examine every aspect of how your blood was obtained, handled, and tested — and will pursue every legitimate avenue to challenge results that were obtained improperly or that cannot withstand scrutiny.
