In outpatient CDI and coding, the Official ICD-10-CM Guidelines that apply are the universal rules plus the outpatient-specific rules. Section I contains conventions, general coding guidelines, and chapter-specific guidance that govern code assignment in every setting (e.g., code structure, “use additional code,” laterality, sequencing instructions, and condition-specific rules). Section IV is specifically written for outpatient services and drives core outpatient behaviors such as selecting the “first-listed” diagnosis based on the main reason for the encounter, reporting additional diagnoses that are evaluated/assessed/treated or impact care, and applying outpatient-only restrictions (for example, diagnoses documented as “rule out,” “probable,” or “suspected” generally are not coded in outpatient the way they may be for inpatient reporting). ACDIS outpatient CDI education emphasizes teaching providers to document clearly the reason for visit, the assessment/clinical relevance of each condition addressed, and the linkage between conditions and services rendered so Section I and Section IV rules can be applied accurately for compliant reimbursement and reporting.