Breath Tests in Maryland DUIs: PBT vs. Police Station Results

 Posted on July 15, 2025 in DUI

If you are pulled over in Maryland on suspicion of DUI, you may be asked to take a Preliminary Breath Test, also known as a Portable Breath Test (PBT). This is a handheld breathalyzer used to determine probable cause for arrest. It is essential to note that, unlike the more accurate breathalyzer test administered at the police station, the PBT is not admissible in court and can be refused without incurring any legal penalty, just like field sobriety tests.

The police station breathalyzer (often an Intoxilyzer or Intoximeter) is administered under strict protocols, resulting in a "formal" Blood Alcohol Concentration (BAC) reading and is legally binding under Maryland’s implied consent law. To be clear, you can refuse the PBT without facing immediate legal consequences for doing so.

That said, refusing a PBT can provide the officer with probable cause to arrest you for DUI, and refusing the station breathalyzer can result in a license suspension. If you are facing DUI charges, the best step you can take is to speak to an experienced Silver Spring, MD DUI lawyer who can immediately begin building a solid defense on your behalf.  

Preliminary Breathalyzer Tests vs. Station Breathalyzer Tests

Preliminary breath tests are less accurate than station breathalyzers due to environmental fluctuations, infrequent calibrations, and lower overall accuracy resulting from their portable use. Since PBTs are used to gain probable cause for a DUI arrest if an attorney can demonstrate the problems associated with PBTs, the entire arrest may be dismissed. PBTs are prone to error, and as a result, their results are not typically admissible as primary evidence in court.

Improper calibration, errors in administration, and inadequate maintenance increase the risk of error. In particular, regular calibration is crucial to the accuracy of PBTs, yet they may not be calibrated on a regular basis. Scientific research can be used to highlight the limitations of PBTs and challenge their reliability. A station Intoxilyzer or Intoximeter, on the other hand, must be strictly maintained in accordance with state guidelines.

The results of a breathalyzer test at a station are accepted in court as evidence, and a refusal triggers implied consent penalties, including a license suspension. While station breathalyzers can still be scrutinized regarding officer training and calibration, these machines are considered much more reliable than PBTs. Even so, there are many potential challenges to the station breathalyzer test results, including medical issues of the defendant, prescription drugs, age, gender, and more.

If a PBT and Field Sobriety Tests Are Refused, Where is the Probable Cause?

If the PBT and field sobriety tests are refused, it might seem as though there is no probable cause for a DUI arrest. Unfortunately, probable cause can still be established by other observations by the arresting officer, such as:

• Driving behaviors such as speeding, erratic lane changes, weaving, or other traffic violations.
• A strong odor of alcohol
• The driver’s physical appearance, including slurred speech, bloodshot eyes, or unsteady balance.
•  Any statements made by the driver that suggest he or she was driving under the influence.

Contact a Montgomery County, MD DUI Lawyer

If you have been pulled over and asked to submit to a breath test – whether portable or at the station – it is crucial that you understand your rights along with the legal weight of each test. A knowledgeable Silver Spring, MD DUI attorney from The Law Offices of Gerstenfield & Demirji, PC. can challenge errors like improper procedures, uncalibrated equipment, or failure to Mirandize you or allow you to call an attorney.

It is important not to leave your future to chance. As soon as you are placed under arrest, contact one of our compassionate, aggressive attorneys. We have solid relationships with prosecutors, which benefit our clients, and are available 24/7. Additionally, we are fluent in Arabic and Spanish. Call 301-589-9500 to schedule your free consultation.