Blood Tests

How We Challenge the Evidence

Blood test evidence in a Georgia DUI case is governed by O.C.G.A. § 40-6-392 and by strict scientific protocols. Unlike a breath test — which produces an immediate number — a blood draw creates a biological sample that must be properly collected, preserved, transported, stored, and analyzed for the result to be reliable. Each step in that chain is a potential challenge point.

Key blood draw requirements in Georgia

Only a qualified person may draw the blood (physician, registered nurse, certified medical technician, or trained law enforcement officer). The standard Georgia DUI blood draw kit (TriTech BU-3) uses gray-top BD Vacutainer tubes containing sodium fluoride (NaF) and potassium oxalate. These tubes require 8–10 complete end-over-end inversions immediately after collection to ensure the preservative mixes with the blood sample. Failure to properly invert creates conditions for fermentation — a process that produces ethanol in the tube, resulting in an artificially elevated BAC reading.

Chain of custody

Every person who handled the sample — from the officer at the scene to the phlebotomist to the evidence technician to the GBI Crime Lab analyst — must be documented. Gaps or inconsistencies in the chain of custody create reasonable doubt about whether the tested sample is the same sample drawn from the defendant.

GBI Crime Lab analysis

Georgia DUI blood samples are analyzed using headspace gas chromatography, the gold standard for forensic BAC analysis. Willis Law Firm challenges GBI lab results by examining calibration standards used during the analysis run, reagent and calibrator lot numbers, analyst certification, and whether duplicate testing (required by GBI protocol) was performed and reported.

The Manning Order (March 2026)

Greg Willis obtained a ruling from Cobb County State Court declaring O.C.G.A. § 40-6-392(d) unconstitutional as applied under both the Fourth Amendment and the Georgia Constitution’s search and seizure protections. This ruling is now part of the legal landscape for blood draw DUI cases in Georgia and is actively being asserted in relevant cases.