An Invalid Sample of a DUI Breath Test

The Washington State Patrol provides the DataMaster Operator Information Manual for training a police officer about the BAC breath test administration.

If an individual is under arrest for Driving Under the Influence they will be taken to the police station for further investigation. The arresting police officer will read the Implied Consent Warnings to the DUI suspect. The DUI suspect must decide whether or not to submit breath test samples.

Washington State uses two breath test machines: The BAC DataMaster and the DataMaster CDM. When the DUI suspect provides two samples the DataMaster will produce a Breath Test Document as seen below:

Across from Subject Sample are the breath test results. In the picture above the breath test results are .138 and .137. The BAC DataMaster is programmed to detect various errors during the administration of the breath test. One such error is the Invalid Sample.

An Invalid Sample means mouth alcohol is being detected, the subject is not providing a proper sample, or the DataMaster is out of adjustment. When the DataMaster registers an Invalid Sample the investigating police officer must conduct another mouth check and an additional 15 minute observation period. Afterwards, the police officer will administer the breath test again.

If an Invalid Sample occurs again, the police officer must decide if the DUI suspect is actually trying to provide a breath or if they are screwing around. If the police officer determines the DUI suspect is playing games, the police officer can enter a breath refusal. A refusal will increase DUI penalties.

If the DUI suspect is really trying to provide a sample and an Invalid Sample is registered a second time, the police officer can transport the DUI suspect to another BAC DataMaster machine. The police officer should also report the Invalid Sample errors to the Washington State Patrol Breath Test Section.