OA-23 — Prior Authorization Required / Other Payer

OA-23 is used when authorization from another payer is needed, or when the payer uses it to deny ongoing therapy authorization. Clarify whether the required authorization is the payer's own or another insurer's (COB context). If the payer is requiring authorization for mental health without a comparable requirement for medical/surgical outpatient services, invoke MHPAEA. Request the NQTL analysis under CAA 2021 § 203.