Most people think a DWI breath test is one quick puff. The Minnesota breath test is more structured than that. Knowing how it works can help you understand what happened at the station, or what to expect.
When police can ask for the test
Under Minnesota’s implied consent law, anyone who drives or is in physical control of a motor vehicle in the state agrees to chemical testing. But the officer needs probable cause that you drove impaired, plus one of these:
- You were lawfully arrested for DWI.
- You were in a crash with property damage, injury, or death.
- You refused the preliminary screening test.
- The screening test showed 0.08 or more.
What you must be told first
Before the breath test, the officer must read you what’s called the breath test advisory. It covers three things:
- Minnesota law requires you to take a test.
- Refusing a breath test is a crime.
- You have the right to talk to a lawyer, but only if it doesn’t unreasonably delay the test.
How the machine test runs
The test isn’t one sample. It must follow a set order: one breath sample, one control check, and then a second breath sample.
A sample is “adequate” if the machine analyzes it and doesn’t flag it as deficient.
Then the two samples are compared. If they’re within 0.02 of each other, the test is acceptable. If they’re further apart, the test is deficient. After a deficient test, the officer must give a second test.
When a test turns into a refusal
This is the part that surprises people. For license revocation, the law treats two things as a refusal:
- Not giving two separate, adequate samples in the right order.
- Two deficient tests.
So a person who never said “no” can still be treated as refusing for license purposes. That matters, because a refusal brings its own license consequences. This breakdown of what refusing a breath test in Minnesota can cost you explains the criminal and license side in plain terms.
Your right to a second test
You have the right to have someone you choose give you an additional test. There are limits. It has to happen where you’re in custody, after the officer’s test, and at no cost to the state.
If you can’t get one, the officer’s test can still be used as evidence. The exception is when the officer prevented or denied your test.
If you can’t respond
A person who is unconscious, or in a state where they can’t refuse, is treated as not having taken back their consent. The test may be given.
Who can draw blood
Only certain trained people may draw blood for a DWI test. The list includes a doctor, a registered nurse, a phlebotomist, or another qualified person acting at an officer’s request. That limit does not apply to breath or urine samples.
Tips if you’re facing a DWI case
A few notes made early can help later.
- Write down what happened at the station while you still remember.
- Note how many times you were asked to blow.
- Keep every paper the officer gave you.
- Note whether you asked for your own additional test, and what happened.
- Talk to a lawyer about the test records early, before any deadline passes.
Read the law
The full testing rules are in section 169A.51 of Minnesota Statutes. Subdivision 5 covers the breath machine.
The bottom line
A breath test is a process with rules. When those rules aren’t followed, or when a “refusal” comes from bad samples, the details can matter a great deal.