What kind of device is a portable breath testing device?

A portable breath testing device serves primarily as a preliminary screening tool for alcohol, which is why this choice is the most accurate. These devices are designed to measure the concentration of alcohol in a person's breath, providing an initial assessment of whether an individual may be under the influence of alcohol. This function is crucial in various situations, such as traffic safety checks or workplace assessments.

While the device could be used in legal contexts, such as law enforcement, that aspect does not entirely define its purpose; therefore, it is not the primary reason for its existence. Social events may see the use of such devices, but again, this does not encompass the main function of the device, which is to screen for alcohol. Lastly, suggesting that it is only used in hospitals is incorrect, as portable breath testing devices are widely utilized outside of medical facilities by law enforcement and during field sobriety checks.