Illinois blood evidence chain of custody must trace the sample from draw to laboratory to court. Under 625 ILCS 5/11-501.2 and the Illinois Rules of Evidence, the state must show who drew the blood, when and where, what preservatives were used, who transported the sample, how it was stored, when the seal was broken, who tested it, and how the result was recorded. Every custodian must be documented. Gaps, mislabeling, temperature excursions, or unaccounted possession time undermine admissibility. A Chicago DUI lawyer subpoenas the intake log, storage records, and analyst worksheets. A single unexplained gap can render the result inadmissible under Illinois foundational rules.
