What is the purpose of using a "blank sample" in testing?

Using a "blank sample" in testing serves the important function of ensuring that no residual alcohol or other substances interferes with the accuracy of the test results. Before conducting a test on an individual, running a blank sample allows the operator to verify that the Intoxilyzer 9000 is returning a zero reading or a baseline that indicates the absence of alcohol. This step is crucial because any residual alcohol from previous tests could falsely elevate the reading of an individual's breath alcohol content, leading to inaccurate results. By confirming that the device is free of interference, the integrity of each subsequent test is maintained, ensuring that the results reflect the true alcohol concentration of the person's breath being tested.