735 ILCS 5/8-2101
All information, interviews, reports, statements, memoranda, recommendations, letters of reference or other third party confidential assessments of a health care practitioner's professional competence, or other data of the Illinois Department of Public Health, local health departments, the Department of Human Services (as successor to the Department of Mental Health and Developmental Disabilities), the Mental Health and Developmental Disabilities Medical Review Board, Illinois State Medical Society, allied medical societies, health maintenance organizations, medical organizations under contract with health maintenance organizations or with insurance or other health care delivery entities or facilities, tissue banks, organ procurement agencies, physician-owned insurance companies and their agents, committees of ambulatory surgical treatment centers or post-surgical recovery centers or their medical staffs, or committees of licensed or accredited hospitals or their medical staffs, including Patient Care Audit Committees, Medical Care Evaluation Committees, Utilization Review Committees, Credential Committees and Executive Committees, or their designees (but not the medical records pertaining to the patient), used in the course of internal quality control or of medical study for the purpose of reducing morbidity or mortality, or for improving patient care or increasing organ and tissue donation, shall be privileged, strictly confidential and shall be used only for medical research, increasing organ and tissue donation, the evaluation and improvement of quality care, or granting, limiting or revoking staff privileges or agreements for services, except that in any health maintenance organization proceeding to decide upon a physician's services or any hospital or ambulatory surgical treatment center proceeding to decide upon a physician's staff privileges, or in any judicial review of either, the claim of confidentiality shall not be invoked to deny such physician access to or use of data upon which such a decision was based.
735 ILCS 5/8-2101