Me. Rev. Stat. tit. 28-B, § 604

Except as provided in section 604‑A, if a test to be performed by a testing facility is a mandatory test under section 602, an employee or designee of the testing facility or a sample collector must collect the sample required for the test. If a test to be performed by a testing facility is not a mandatory test, the owner of the cannabis or cannabis product, or a designee of the owner, may collect the sample required for the test.