Wyoming DUI Chemical Testing: Blood, Breath, and Urine Tests Explained

Wyoming DUI cases rely heavily on chemical test evidence, but not all tests carry the same legal weight. There is a critical distinction between the roadside Preliminary Breath Test and the post-arrest evidentiary chemical test at the police station — and confusing the two can lead to decisions you cannot undo.

The Roadside Preliminary Breath Test (PBT)

The PBT is a handheld breathalyzer used at the scene during a traffic stop. It gives the officer a rough BAC reading that helps establish probable cause for a DUI arrest. Key facts about the PBT:

• You can refuse the PBT without triggering implied consent penalties. The roadside PBT is not the same as the post-arrest evidentiary test. Refusing the PBT does not automatically trigger the 6-month administrative license suspension that comes with refusing the evidentiary test.
• PBT results are generally not admissible as evidence of your exact BAC at trial. They are used primarily to support the officer's probable cause determination.
• The officer may still arrest you even if you refuse the PBT. Other observations — field sobriety test performance, slurred speech, odor of alcohol, driving behavior — can independently establish probable cause.

The Post-Arrest Evidentiary Chemical Test

This is the test that matters for both your criminal case and your administrative license suspension. After a lawful arrest, the officer transports you to the station (or a medical facility) for an evidentiary chemical test. Under Wyoming's Implied Consent Law (W.S. § 31-6-102), you have already consented to this test by operating a vehicle on Wyoming's roads.

Wyoming uses three types of evidentiary tests:

Breath test (Intoximeter): The most common. You blow into a calibrated device at the station that measures BAC. The calibration records and maintenance logs of this device are critical evidence — defense attorneys routinely request them during discovery to check for errors.

Blood test: Used when the officer suspects drug impairment, when a breath test is unavailable, or when you are taken to a hospital after an accident. Blood draws must follow specific chain-of-custody and lab protocols. A blood test can detect both alcohol and controlled substances.

Urine test: Less common, but may be requested when the officer suspects controlled substance impairment and a blood draw is not immediately practical. Urine tests are less precise for measuring current impairment compared to blood tests.

The officer typically chooses which test to administer. You do not get to pick.

What Happens When You Refuse the Evidentiary Test

Refusing the post-arrest evidentiary chemical test triggers serious administrative consequences under implied consent:

• 6-month administrative license suspension — double the standard 90-day suspension for a failed BAC test
• Ineligibility for a probationary (hardship) license — refusal drivers cannot get the standard restricted driving permit
• IIRL is your only option — the Ignition Interlock Restricted License is the sole legal driving option, and you must wait 45 days of hard suspension before you can apply
• The refusal goes on your WYDOT administrative record regardless of the criminal case outcome

Even after a refusal, law enforcement can obtain a warrant (sometimes called an e-warrant) to compel a blood draw. This means refusing the test may not actually prevent chemical evidence from being collected — but the administrative penalties for the refusal still apply.

How Testing Results Affect Your Case

The evidentiary test result determines two critical things:

1. Administrative track (WYDOT): BAC of 0.08%+ triggers a 90-day suspension. BAC of 0.15%+ or refusal triggers the IIRL requirement. The 20-day hearing request deadline applies regardless of the result.
2. Criminal track (circuit court): The BAC result is the prosecution's primary evidence. Defense attorneys analyze the calibration records, the time between arrest and testing, and whether testing protocols were followed correctly.

A BAC between 0.08% and 0.14% keeps you eligible for a probationary license on the administrative side. A BAC of 0.15% or higher pushes you into the interlock-only category, which costs significantly more.

The Bottom Line on Testing

The practical takeaway: the roadside PBT and the post-arrest evidentiary test serve different purposes and carry different consequences. Understanding which is which — and what refusing each one means — is essential for making informed decisions during a DUI stop.

The Wyoming First-Offense DUI Guide covers how chemical test results flow into both the WYDOT administrative suspension and the criminal court case, including how to request the calibration records that could matter to your defense.

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