What should a subject be instructed to do during a breath test?

During a breath test with the Intoxilyzer 9000, a subject should be instructed to take a deep breath and blow until the tone sounds. This procedure is essential because it ensures that the breath sample collected is adequate and maximally representative of the subject's breath alcohol concentration.

Taking a deep breath helps to fill the lungs with air, ensuring that the sample taken is from the deep lung, where alcohol is absorbed into the bloodstream. The instruction to blow until the tone sounds is important because it indicates that the machine has detected enough air flow and is successfully collecting the sample. If a subject blows too forcefully or too quickly, it may not provide a complete or accurate sample, leading to potential errors in the alcohol concentration readings.

Focusing on this method not only helps in obtaining a valid test but also aligns with the operational protocol designed to yield reliable results.