No Ghost in the Machine: Why a “Failed” Breathalyzer Does Not Equal an OUI Conviction in 2026

If you took a breathalyzer test at a Massachusetts police station and registered a Blood Alcohol Content (BAC) of .08 or higher, the police and the prosecutor will treat the case as if it is already over. They rely on the psychological weight of that number to force defendants into accepting a “Continuance Without a Finding” (CWOF) or a guilty plea at their very first court appearance.

For the licensed professional, the CDL holder, or the university student, accepting a plea deal based solely on a breathalyzer machine’s numbers can be a mistake.

In the Massachusetts district courts of 2026, a “failed” breathalyzer is simply the beginning of the defense. Serpa Law Office approaches OUI defense with a fundamental skepticism of government forensic science. Here is how we forensically review the Commonwealth’s breathalyzer evidence before it can be used to permanently alter your record.

1. The Roadside “Portable” Test is Inadmissible at Trial

One of the most common sources of panic for a defendant is the “Portable Breath Test” (PBT) administered on the side of the road. Officers often use these handheld devices to justify an arrest.

What the police do not tell you is that the results of a roadside PBT are strictly inadmissible in a Massachusetts trial.These handheld units are notoriously unreliable, susceptible to temperature changes, and lack the already weak forensic safeguards of station-house machines. Whether you blew a .09 or a .15 on the side of Route 128, that number cannot be presented to a jury to prove you were operating under the influence.

2. The Achilles Heel: The 15-Minute Observation Period

If you are arrested and transported to the station, the police will ask you to submit to the official breathalyzer, the Draeger Alcotest 9510.

Before the officer can even turn this machine on, Massachusetts law mandates a strict 15-minute observation period.The officer must continuously observe you for a full 15 minutes to ensure you do not burp, hiccup, regurgitate, or put anything in your mouth. Why? Because the Draeger 9510 is designed to measure deep lung air. A burp brings “mouth alcohol” up from the stomach, which can artificially inflate a breathalyzer reading by hundreds of percentage points.

Serpa Law Office obtains all video, including the booking room video, for our OUI clients. In busy police stations like Cambridge, Quincy, or Boston, officers handle paperwork, cell phones, or other detainees during this critical window. If we can prove the officer broke visual contact with you for even a moment, we file a Motion to Suppress the breathalyzer results entirely.

3. The Calibration Problem: The Ghost of the Office of Alcohol Testing

Breath test results are not the product of infallible science. The history of breath testing in Massachusetts is plagued by institutional error and a little bad faith.

In recent years, the statewide Commonwealth v. Ananias litigation exposed that the Massachusetts Office of Alcohol Testing (OAT) had intentionally hidden hundreds of failed calibration worksheets from defense attorneys, resulting in the exclusion of over 27,000 breath tests.

Do not take the Prosecution’s word for it when they claim the Draeger machines are now properly calibrated. Demand the specific calibration logs, maintenance records, and diagnostic checks for the exact machine used in your arrest. If the machine was overdue for its annual certification, or if it had a history of returning “interferent detected” error messages, you can challenge its scientific reliability under the Daubert-Lanigan standard.

4. The “Two-Breath” .02 BAC Variance Rule

Massachusetts law requires that a defendant provide two separate breath samples into the Draeger 9510 to ensure accuracy.

The regulations require that the two samples read within 0.02% of each other. If your first breath is a .09 and your second breath is a .12, the machine has failed its own internal consistency check. The results are invalid. Furthermore, the Supreme Judicial Court has ruled that only the lower of the two readings can be admitted into evidence..

The Trial Strategy: We Don’t Just Fight the Machine, We Fight the Narrative

Even if the breathalyzer result is admitted into evidence, it is not an automatic guilty verdict. A .08 reading is simply a “per se” violation; it does not erase the other evidence of your sobriety.

Juries are inherently skeptical of machines. They demand rigorous scientific support especially where all other roads point to sobriety. At trial, your lawyer must juxtapose the sterile, arbitrary number of the breathalyzer against the human reality of your arrest. Body cam and booking video showing you speaking clearly, answering questions correctly, and walking with perfect balance, we force the jury to ask a logical question: My own eyes show me a person who is perfectly sober. Why would I trust a machine over my own judgment and observation?

Take Control of Your Defense

A digital result from a police station breathalyzer does not seal your fate. The administration of a breath test is a technical procedure performed by human officers who can make procedural errors.

If you have been charged with an OUI in Eastern Massachusetts or Greater Boston, find an attorney who understands the mechanical vulnerabilities of the Draeger 9510 and the constitutional requirements for its admissibility.

Contact Serpa Law Office for a rigorous review of the forensic evidence used against you and a trial-tested defense necessary to protect your license, your career, and your future.