215 ILCS 200/25
Notwithstanding any other provision of law, if a health insurance issuer requires prior authorization of a health care service, the health insurance issuer or its contracted utilization review organization must make an approval or adverse determination and notify the enrollee, the enrollee's health care professional, and the enrollee's health care provider of the approval or adverse determination as required by applicable law, but no later than 5 calendar days after obtaining all necessary information to make the approval or adverse determination. As used in this Section, "necessary information" includes the results of any face-to-face clinical evaluation, second opinion, or other clinical information that is directly applicable to the requested service that may be required.
215 ILCS 200/25