In many Colorado alcohol DUI investigations, the driver must receive a meaningful opportunity to choose between a blood test and a breath test. Neither option is universally better. The defensible question is whether police honored the choice, followed the required procedure, and accurately characterized any failure to complete testing.
Drug investigations work differently. When drugs are suspected, Colorado law may allow the officer to direct the type of chemical test rather than offer the same blood-or-breath choice used in alcohol cases.
A Denver DUI lawyer can review the advisement, video, testing records, and refusal designation instead of treating the reported number as the entire case.
Blood and Breath Produce Different Evidence
A breath test estimates alcohol concentration through an approved instrument. It generally produces a result sooner and depends on a documented observation period, instrument certification, and an adequate breath sample.
A blood test measures the submitted sample through laboratory analysis. It creates a preserved sample and a laboratory record that may be reviewed or independently tested, but collection, storage, chain of custody, and analysis can become disputed.
Those differences affect defense investigation. They do not create a simple rule that one test always helps the driver.
Alcohol Cases Generally Require a Meaningful Choice
Colorado’s Express Consent law governs post-arrest chemical testing. In an alcohol case, officers generally advise the driver of blood and breath options unless an exception makes one unavailable.
A choice is not meaningful if the selected test is never reasonably provided and the driver is then blamed for refusing it. Review should focus on the exact words used, the driver’s response, whether the chosen test was available, and what happened next.
The label “refusal” may conceal a failed testing process rather than a deliberate decision not to cooperate.
Inability to Complete a Test Is Not Always a Simple Refusal
A driver may select breath testing but become physically unable to complete the required observation period. If the officer records that event as a refusal, the defense should examine whether the driver deliberately declined testing or whether the selected test was never provided through a workable procedure.
That fact pattern does not guarantee dismissal. It raises specific questions:
- Did the driver clearly select breath?
- Did illness prevent completion?
- What did the officer say after the interruption?
- Was another lawful test offered or requested?
- Does the video match the refusal narrative?
- Did the driver intentionally decline or fail to cooperate?
The answers can affect both the DMV revocation and the criminal case.
Drug Cases Do Not Use the Same Choice Rule
Breath testing cannot establish the concentration of most drugs. When an officer has probable cause to believe drugs are involved, blood, urine, or another authorized specimen may be requested under the governing law.
The meaningful-choice rule used in alcohol cases should not be imported into every drug DUI. The suspected substance and statutory basis for the requested test matter.
A driver may also face a mixed alcohol-and-drug investigation. That makes the officer’s advisement and stated basis for each request especially important.
Testing Procedure Can Matter as Much as the Result
For breath testing, counsel may examine the observation period, instrument records, operator certification, maintenance history, sample agreement, and physiological events that could affect the test.
For blood testing, review may include the collection kit, collector qualifications, tube condition, preservatives, sealing, chain of custody, laboratory method, quality-control data, and any available retained sample.
Not every imperfection excludes a result. The defect must be connected to admissibility, reliability, statutory compliance, or the weight a factfinder should give the number.
Get the Testing Sequence Reviewed
Keep every DMV notice and testing document. Counsel can seek body-camera video, dispatch records, breath-room video, instrument records, blood-kit documentation, and laboratory data.
Write down what you remember about the advisement and your physical condition, but do not contact the officer or laboratory to argue the case yourself. A casual explanation can become another statement for the prosecution.
Prager Law reviews the complete chemical-test sequence to determine whether the state obtained valid evidence or merely assigned a damaging label. For help reviewing a blood, breath, or refusal case, call 303-483-4452 or contact Prager Law.
