The 2026 DRG Desk Reference gives access to crucial information to improve MS-DRG assignment practices, guidance on how to accurately assign DRGs under the MS-DRG system and focuses on the Optimizing section of the DRG Desk Reference based on ICD-10 codes. The DRG Desk Reference is designed to work hand-in-hand with Optum’s DRG Expert. These products will answer all your DRG questions for all inpatient stays starting after October 1, 2025, as those claims will use the MS-DRG methodology based on ICD-10-CM.