How long should an operator observe a subject before administering the test?

The correct duration for observing a subject before administering the Intoxilyzer 9000 test is 20 minutes. This observation period is crucial to ensure that the subject does not ingest any substances that could interfere with the test results, such as alcohol or food. The 20-minute timeframe allows the operator to confirm that the subject is in a stable condition and has not regurgitated, thus providing a more accurate measurement of alcohol content. Proper adherence to this protocol helps to uphold the integrity of the testing process and ensures the reliability of the results derived from the Intoxilyzer machine.