ICD-10-CM Official Guidelines for Coding and Reporting (FY 2027)
by CMS & NCHS (Cooperating Parties) · Centers for Medicare & Medicaid Services
The rulebook every coder and every certification exam tests against; no substitute exists. The HIPAA-mandated rules for assigning ICD-10-CM diagnosis codes, approved by CMS, NCHS, AHA and AHIMA. Covers code conventions, chapter-specific guidance, sequencing, and separate rules for inpatient versus outpatient reporting. Effective October 1, 2026.
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