ICD-10-CM (International Classification of Diseases, 10th Revision, Clinical Modification) is the standard diagnostic coding system used across U.S. healthcare for billing, documentation, and statistical reporting. Whether you're preparing for the CPC, CCS, or RHIT certification exam, mastering ICD-10 code structure and official guidelines is essential. This free printable PDF gives you real exam-style questions you can study anywhere — no internet required.
ICD-10-CM codes follow a precise alphanumeric structure: the first character is always a letter, followed by two numeric digits, a decimal point, and up to four additional characters. The seventh character extension is used for injuries and fractures to specify the encounter type. Understanding how each character position conveys clinical meaning is the foundation of accurate coding.
Accurate ICD-10-CM coding requires understanding both code structure and the Official Guidelines for Coding and Reporting, updated annually by CMS and the National Center for Health Statistics. The guidelines govern how coders sequence diagnoses, when to code signs and symptoms versus definitive diagnoses, and how to handle chronic versus acute conditions.
For inpatient encounters, the principal diagnosis is the condition determined after study to be chiefly responsible for the admission. For outpatient encounters, coders assign a first-listed diagnosis — the main reason for the visit. When a definitive diagnosis has not been confirmed, outpatient coders report signs, symptoms, and abnormal findings rather than uncertain diagnoses.
Fracture coding uses seventh characters to indicate the episode of care: A for the initial encounter when active treatment is provided, D for subsequent encounters during healing, and S for sequela (late effects). Additional characters distinguish open from closed fractures and displaced from non-displaced fractures, making specificity critical for accurate reimbursement.
The diabetes mellitus codes (E08–E13) are combination codes that capture both the type of diabetes and any associated complications in a single code. E11 covers Type 2 diabetes with subtypes for complications such as diabetic nephropathy (E11.21), diabetic retinopathy (E11.3x), and peripheral neuropathy (E11.40). E10 covers Type 1 diabetes with the same complication structure.
The neoplasm table in the ICD-10-CM Alphabetic Index is the primary lookup tool for cancer coding. Codes vary by behavior — primary malignancy, secondary (metastatic) malignancy, carcinoma in situ, benign, uncertain behavior, or unspecified. Coding from the wrong column is one of the most common errors on certification exams.
The two most widely recognized medical coding credentials are the AAPC's Certified Professional Coder (CPC) and AHIMA's Certified Coding Specialist (CCS). Both exams test ICD-10-CM diagnostic coding alongside procedural coding systems. The CPC is primarily outpatient-focused (physician office and clinic), while the CCS emphasizes inpatient hospital coding and DRG assignment.
The RHIT (Registered Health Information Technician) exam from AHIMA includes a medical coding domain covering ICD-10-CM, ICD-10-PCS, and CPT. All three credentials require a deep understanding of the Official Guidelines, sequencing rules, and code specificity requirements.
Using this free PDF alongside timed practice tests helps you build both accuracy and speed — essential for passing under real exam conditions where you have limited time per question. Focus on high-yield areas like diabetes coding, neoplasm table navigation, fracture 7th character selection, and outpatient vs. inpatient sequencing rules.