The 2026 ICD-10-CM Expert for Hospitals, with our hallmark features and format, makes facing the challenge of accurate diagnosis coding easier for acute care and long-term care hospitals (LTCH). This code book contains the complete ICD-10-CM code set, the 2026 ICD-10-CM Official Guidelines for Coding and Reporting, and the familiar Optum coding and reimbursement alerts for facility coding. This includes, MCEs, and ICD-10 MS-DRG edits with symbols identifying codes for comorbidities/complications (CC) and major comorbidities/complications (MCC). Also identified are hospital acquired conditions (HAC), CMS hierarchical condition categories (HCC), and present on admission (POA)