ICD-10-CM Cheatsheet

Cheatsheet Content

What is ICD-10-CM? International Classification of Diseases, 10th Revision, Clinical Modification. Used for diagnosis coding in all healthcare settings in the USA. Maintained by the National Center for Health Statistics (NCHS). Provides a common language for reporting diseases, injuries, and causes of death. Code Structure ICD-10-CM codes are 3 to 7 characters long, with a decimal point after the third character. Character 1: Alphabetic (A-Z, excluding U) Character 2: Numeric Character 3: Numeric or Alphabetic Characters 4-6: Numeric or Alphabetic (provide greater specificity) Character 7: Alphabetic or Numeric (extension for injuries/external causes) Example: $S02.5XAD$ $S$: Chapter S (Injuries, Poisoning, and Certain Other Consequences of External Causes) $02$: Fracture of skull and facial bones $.5$: Fracture of tooth $X$: Placeholder character (used when a code has fewer than 6 characters but requires a 7th character) $A$: Initial encounter $D$: Subsequent encounter Key Features Increased specificity and clinical detail. Laterality (left/right) is often specified. Combination codes for conditions and common symptoms. Expanded codes for injuries, including specific encounter types. Placeholder character 'X' for future expansion and to allow for 7th character. Excludes1 and Excludes2 notes. 7th Character Extensions (Common for Injuries/External Causes) Character Meaning $A$ Initial encounter (active treatment) $D$ Subsequent encounter (routine healing) $S$ Sequela (complications or conditions arising as a direct result of a condition) $B, C, E-R$ Other specific encounter types (e.g., $B$ for initial encounter with fracture nonunion) Excludes Notes Excludes1: "NOT CODED HERE!" - Indicates two conditions that cannot occur together (e.g., congenital vs. acquired form of the same condition). Excludes2: "NOT INCLUDED HERE!" - Indicates two conditions that are separate but may occur together. It is acceptable to code both conditions if they are present. General Coding Guidelines Code to the highest level of specificity (use all available characters). Locate the main term in the Alphabetic Index, then verify in the Tabular List. Always read and follow instructional notes (e.g., Includes, Excludes1, Excludes2, Code Also, Use Additional Code). Code confirmed diagnoses. Do not code "rule out," "suspected," or "possible" diagnoses in outpatient settings. For "probable" or "suspected" diagnoses in inpatient settings, code as if confirmed. Signs and symptoms are coded when a definitive diagnosis has not been established. Commonly Used Chapters (Examples) Chapter Range Description Example Code $A00-B99$ Infectious and Parasitic Diseases $A41.9$ (Sepsis, unspecified organism) $C00-D49$ Neoplasms $C50.919$ (Malignant neoplasm of unspecified part of unspecified female breast) $E00-E89$ Endocrine, Nutritional, Metabolic Diseases $E11.9$ (Type 2 diabetes mellitus without complications) $I00-I99$ Diseases of the Circulatory System $I10$ (Essential (primary) hypertension) $J00-J99$ Diseases of the Respiratory System $J45.909$ (Unspecified asthma, uncomplicated) $K00-K95$ Diseases of the Digestive System $K21.9$ (Gastro-esophageal reflux disease without esophagitis) $M00-M99$ Diseases of the Musculoskeletal System & Connective Tissue $M25.561$ (Pain in right knee) $N00-N99$ Diseases of the Genitourinary System $N39.0$ (Urinary tract infection, site not specified) $R00-R99$ Symptoms, Signs, Abnormal Clinical & Lab Findings, NEC $R51$ (Headache) $S00-T88$ Injury, Poisoning, & Certain Other Consequences of External Causes $S82.311A$ (Displaced transverse fracture of shaft of right tibia, initial encounter for closed fracture) $Z00-Z99$ Factors Influencing Health Status & Contact with Health Services $Z00.00$ (Encounter for general adult medical examination without abnormal findings) Important Considerations Laterality: Always specify left or right when indicated (e.g., $M25.511$ Pain in right shoulder). Underlying Condition: Code the underlying condition first, then any specific manifestations. Complications: Code complications when present and supported by documentation. Documentation: Accurate and thorough clinical documentation is crucial for correct coding. Outpatient vs. Inpatient: Coding guidelines can differ for certain scenarios (e.g., probable diagnoses). Using the Alphabetic Index and Tabular List Alphabetic Index (Volumes 2 & 3) Locate the main term for the patient's condition (e.g., "Fracture," "Diabetes," "Hypertension"). Follow any cross-references ("see," "see also"). Note any subterms that provide greater specificity. Identify the preliminary code(s). Tabular List (Volume 1) Verify the preliminary code(s) from the Alphabetic Index. Read all chapter, section, category, and subcategory notes. Pay attention to "Includes," "Excludes1," "Excludes2," "Code Also," "Use Additional Code" instructions. Select the most specific code available, including any 7th character extensions, if applicable.