405 ILCS 5/3-753
If no certificate was filed, the respondent shall be examined separately by a physician, clinical psychologist, advanced practice psychiatric nurse, or qualified examiner and by a psychiatrist. If a certificate executed by a psychiatrist was filed, the respondent shall be examined by a physician, clinical psychologist, qualified examiner, advanced practice psychiatric nurse, or psychiatrist. If a certificate executed by a qualified examiner, clinical psychologist, advanced practice psychiatric nurse, or a physician who is not a psychiatrist was filed, the respondent shall be examined by a psychiatrist. The examining physician, clinical psychologist, qualified examiner, advanced practice psychiatric nurse, or psychiatrist may interview by telephone or in person any witnesses or other persons listed in the petition for involuntary admission. If, as a result of an examination, a certificate is executed, the certificate shall be promptly filed with the court. If a certificate is executed, the examining physician, clinical psychologist, qualified examiner, advanced practice psychiatric nurse, or psychiatrist may also submit for filing with the court a report in which his or her findings are described in detail, and may rely upon such findings for his opinion that the respondent is subject to involuntary admission. Copies of the certificates shall be made available to the attorneys for the parties upon request prior to the hearing.
405 ILCS 5/3-753