Which of the following is NOT one of the three chemical tests used in OUI cases?

In the context of Operating Under the Influence (OUI) cases, chemical tests are utilized to measure a person's blood alcohol concentration (BAC) and the presence of drugs. The three primary chemical tests used in OUI cases are blood, breath, and urine tests.

The blood test measures the actual alcohol content in the bloodstream, providing definitive evidence of impairment. The breath test is commonly used by law enforcement due to its ease of administration and quick results, often using devices like breathalyzers. The urine test, while less commonly used than blood or breath tests, can still serve as an alternative for circumstances where other tests may not be applicable or available.

Saliva tests, while they can detect drugs and alcohol, are not typically included among the standard three tests used in OUI situations in many jurisdictions, including Maine. They may be used in other contexts but do not constitute one of the primary tests for establishing OUI violations, which is why saliva is the correct answer for this question.