Medical Coding Chapter 2 Review (70+ Q&A) – ICD-10-CM/PCS, GEMs, Index Rules, Conventions | 2025/2026

This expertly structured study guide includes over 70 chapter-based questions and correct answers from Medical Coding Chapter 2, focused on mastering the ICD-10-CM and ICD-10-PCS systems, their development, structure, and real-world coding conventions. Updated for 2025/2026, this review is tailored for students preparing for diagnostic and procedural coding exams or advancing into inpatient coding roles. Topics covered include: Origins and responsibility: ICD-10-CM issued by WHO in 1993; maintained in the U.S. by NCHS and CMS for procedural coding (ICD-10-PCS) GEMs (General Equivalence Mappings): Forward and backward mapping between ICD-9 and ICD-10; Approximate flags, “no map,” and combination code indicators ICD-10-CM improvements: Increased specificity, diabetes code updates, combination codes, and new subclassifications for ambulatory care Coding process: Proper sequencing using the Alphabetic Index and Tabular List, verifying code placement, and ensuring code completion with subclassification and 7th characters ICD-10-PCS structure: 7-character format, use in inpatient hospital settings for surgical, diagnostic, and therapeutic procedures Code conventions and symbols: Brackets, parentheses, colons, NEC, NOS, “excludes1” and “excludes2” notes, “code also,” default codes, and cross-references like “see also” Alphabetic Index details: Main terms, subterms, carryover lines, connecting words (e.g., “with,” “due to”), and the importance of checking the tabular list for full accuracy Structural hierarchy: Chapters → Sections → Categories → Subcategories → Subclassifications, including differences in bold vs. italic text for code types and exclusions Ideal for: Medical coding students preparing for CPC, CCS, or HIM exams Instructors teaching ICD-10 foundations Healthcare professionals transitioning to ICD-10 or needing compliance refreshers Coders working with GEMs or crosswalking legacy data Keywords: ICD-10-CM, ICD-10-PCS, diagnosis coding, GEMs, combination codes, ICD-9 transition, coding conventions, alphabetic index, tabular list, excludes notes, NEC, NOS, 7th characters, default codes, CMS, NCHS, WHO, code structure, inpatient coding