405 ILCS 5/3-208

Whenever a petition has been executed pursuant to Section 3-507, 3-601 or 3-701, and prior to this examination for the purpose of certification of a person 12 or over, the person conducting this examination shall inform the person being examined in a simple comprehensible manner of the purpose of the examination; that he does not have to talk to the examiner; and that any statements he makes may be disclosed at a court hearing on the issue of whether he is subject to involuntary admission. If the person being examined has not been so informed, the examiner shall not be permitted to testify at any subsequent court hearing concerning the respondent's admission.