Breathe deep ​the science of preliminary screening tests, or, sometimes called preliminary breath tests or, as the Iowa Department of Public Safety likes to call them, portable breath tests, is that alcohol can be measured in grams per 210 L breath to extrapolate an equivalent to the amount of alcohol that is contained in 100 ml blood. The preliminary breath screen requires reasonable grounds to believe that someone has violated Iowa Code 321J.2, the drunk driving statute in Iowa, or that an suspected motor vehicle operator has been involved in an accident resulting in injury or death. A so-called "passive sample" cup appears not to require a volumetric measurement of deep lung breath. An officer who used one in the field told a trainee he did not consider it a PBT at all and he noted that the machine does not measure g/210 L breath-- it merely shows a "positve" or "negative" ETOH result. Nevertheless, the Iowa Supreme Court has held that a PBT test result cannot be admitted before the jury regardless of whether it is a volumetric measurement or simply a positive or negative result. If you or a loved one has been arrested for OWI (DUI) in Cedar Rapids, Iowa City, or other Iowa community, contact DAC-LAW PLC today for a free initial consultation. Become an informed legal consumer and chart your course back to life before legal crisis. 

Cedar Rapids OWI (DUI) Lawyer: Does the so-called 'passive sample cup' PBT mouthpiece violate Iowa Code 321J.5 requiring reasonable grounds before requesting a preliminary screening test?


Recently, I reviewed a Cedar Rapids, Iowa, OWI (DUI) traffic stop wherein the officer, an experienced SFST administrator, was training someone new. The experienced officer activated emergency top lights for a perceived traffic violation and made contact with the driver and other occupants in the car. He quizzed the driver about consumption of alcohol. Not satisfied with the driver’s answers, he returned to the patrol car and his trainee. He contacted dispatch to indicate he was out with a 10-55, a possibly intoxicated driver, and he said he didn’t believe the driver was being honest about how much he had to drink. He fitted a funnel-like device to the preliminary, or, portable breath test machine and said he was going to talk to the driver again, that the passive mouthpiece when fitted to the PBT would provide a mere positive or negative response—not an amount and that it was “not a PBT.” He apparently thought he could jump straight to a screening test when the PBT was fitted with this questionable device without conducting standardized field sobriety tests, or, SFSTs to establish the reasonable grounds necessary to request a PBT under Iowa Code § 321J.5.

Under the law in Iowa, a law enforcement officer can only request a preliminary screening test when a peace officer has reasonable grounds to believe that either of the following have occurred: (a) A motor vehicle operator may be violating or has violated section 321J.2 or 321J.2A; (b) The operator has been involved in a motor vehicle collision resulting in injury or death.

The device’s manufacturer states that it is “reusable” and meant for “large numbers of suspects,” presumably crowds, either at bars, sporting events, or entertainment venues which makes it seem worse yet— like a general warrantless search.

It remains an open question whether a positive or negative result on this “passive test” mouthpiece impermissibly informs further testing sufficient to suppress it.

If you or a loved one has been arrested for OWI in the State of Iowa, contact DAC-LAW PLC at 319-389-4276 or

generic alcohol breath tester