What does the lower of the two breath samples reflect in a BrAC test?

In a BrAC (Breath Alcohol Concentration) test using devices like the Intoxilyzer 9000, the lower of the two breath samples is significant because it represents the measurement uncertainty that can arise during the testing process. This uncertainty can be due to various factors, such as variations in the breath sample, operator handling, and device calibration.

When the device takes two samples, it looks to ensure reliability and accuracy by comparing the two results. The lower value is often used as a reflection of the most conservative estimate of the actual blood alcohol concentration. This approach aims to account for potential errors or fluctuations in measurement, ensuring that the reported BrAC is not overstated.

Thus, the choice indicating measurement uncertainty captures the essence of using the lower sample value in breath testing protocols.