---
title: "What is the difference between a Portable Breath Test and a station-based breathalyzer?"
description: "Illinois distinguishes the Portable Breath Test from the evidentiary breath machine. The PBT is a roadside handheld device used for pre-arrest screening. Its numerical reading is not admissible at..."
url: https://chicagoduilawyer.net/faq-items/what-is-the-difference-between-a-portable-breath-test-and-a-station-based-breathalyzer/
date: 2026-07-08
modified: 2026-07-08
author: "Chicago DUI Lawyer"
type: faq
lang: en
---

# What is the difference between a Portable Breath Test and a station-based breathalyzer?

Illinois distinguishes the Portable Breath Test from the evidentiary breath machine. The PBT is a roadside handheld device used for pre-arrest screening. Its numerical reading is not admissible at trial on the guilt phase, though its result can support probable cause. The station-based evidentiary instrument, typically an EC/IR II or Datamaster, is calibrated, certified, and operated under Illinois State Police rules and 20 Ill. Adm. Code 1286. Its result is admissible under 625 ILCS 5/11-501.2 when foundation is proven. The 20-minute observation, operator permit, and calibration rules apply only to the evidentiary test. A Chicago DUI lawyer keeps the PBT number out of the guilt phase entirely.