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Ted Agnick | DUI & Criminal Attorney

140 N Montezuma Street
Prescott, AZ 86301

Breathalyzer “False Positives” in Prescott, AZ

Breathalyzer False Positive ArizonaBreathalyzer “False Positives” in Prescott, AZ: What Can Skew Your BAC—and How We Fight It

Pulled over in Prescott and asked to blow? What happens in the next few minutes can define your case. Breath tests are powerful evidence—but they’re not infallible. If you’re staring at a DUI based on a breath result, you still have defenses.

Ted Law | DUI & Criminal Defense – Prescott
(928) 776-1782 • paralegal@tedlaw.net
140 N Montezuma St, Prescott, AZ 86301
Free, confidential case review.

Fast facts (Arizona-specific)

  • Implied consent (A.R.S. § 28-1321): If you refuse a post-arrest breath/blood/urine test, MVD can suspend your license (typically 12 months for a first refusal; 24 months with certain priors).

  • Two kinds of breath tests:

    • Roadside PBT (handheld) = screening only, often not admissible to prove BAC.

    • Evidentiary breath test at the station (e.g., Intoxilyzer) = what the State relies on in court—if foundational rules were followed.

  • Observation period: Officers must conduct a continuous 15-minute deprivation/observation period to prevent “mouth alcohol” contamination.

Where breath results go wrong

1) Human factors / procedure

  • No full 15-minute observation (or it’s interrupted). Burping, belching, regurgitation, recent drinking, or mouthwash can leave alcohol in the mouth and artificially inflate results. If that happens, the observation clock must restart.

  • Improper instructions or blowing technique (short, shallow puffs can confuse the instrument’s “deep lung” sampling).

  • Uncertified operator or incomplete training records.

2) Instrument issues

  • Calibration / accuracy checks not done on schedule, failed, or undocumented.

  • Maintenance lapses (repairs, re-certifications, software versions).

  • Interference (radio frequency, volatile compounds) and filtering logic that isn’t properly validated for your conditions.

3) Physiology & medical conditions

  • Rising BAC: Alcohol absorption can continue 50–180 minutes after your last drink. You might have been under the limit while driving but over by the time you blew.

  • GERD/acid reflux, recent vomiting, or dry heaves can push alcohol vapor from the stomach into the mouth.

  • Diabetes / ketogenic or low-carb diets → elevated acetone; some instruments can misinterpret certain volatiles.

  • Elevated body temperature (fever, exertion) can increase measured breath alcohol compared to true blood alcohol.

4) Medications, products & environment

  • Asthma inhalers, oral sprays, cough syrups, tinctures, mouthwash, breath strips—many contain alcohols or solvents that can spike mouth alcohol.

  • Solvent/paint fumes, alcohol-based sanitizers, adhesives/cleaners—occupational or incidental exposure can contaminate a breath sample if the observation protocol isn’t done right.

How we challenge a Prescott breath test

We don’t accept the number at face value. We demand and dissect:

  • Quality-assurance records: calibration logs, accuracy checks, simulator solutions, maintenance/repair history.

  • Operator credentials & training logs.

  • Observation-period proof: body-cam, dispatch times, forms, and witness accounts.

  • Two-sample agreement: whether duplicate breath tests were within required tolerance.

  • Medical documentation: GERD, diabetes, recent illness, diet/fasting, dental appliances.

  • Timeline analysis: driving time → stop → test time to build a rising-BAC defense.

  • Alternative explanations: mouth alcohol indicators, interfering substances, or procedural shortcuts.

If the State can’t lay a proper scientific foundation, we move to suppress the breath result. If admitted, we present expert testimony to attack reliability and create reasonable doubt.

What to do right now (it helps us help you)

  • Write a timeline (drinks, food, last sip, stop time, test time, any burp/vomit/heartburn).

  • List medications/products used that day (inhalers, mouthwash, sprays).

  • Note symptoms/conditions (reflux, illness, dieting, fever, dental work).

  • Don’t discuss details with anyone but your lawyer.

  • Bring paperwork: citation, release docs, property sheet, any tow/impound info.

Prescott DUI defense, start to finish

Whether you were stopped by Prescott PD, Yavapai County Sheriff, or DPS, we know the local courts and procedures. We handle the criminal case and the separate MVD action, push for charge reductions, evidentiary hearings, and—when needed—trial.

Talk to a Prescott DUI lawyer today

Ted Agnick | DUI & Criminal Attorney
(928) 776-1782 • paralegal@tedlaw.net
140 N Montezuma St, Prescott, AZ 86301
Free consultation • Rapid response • Serious defense

This page is informational, not legal advice. Every case is unique; timelines and outcomes depend on your specific facts.