ICD-10-CM Structure and Conventions Review – Key Terms

International Classification of Diseases, Tenth Revision, Clinical Modification; the U.S. alphanumeric diagnosis coding system. Not Elsewhere Classifiable; used when specific documentation exists but no precise code is available. Not Otherwise Specified; equivalent to 'unspecified'; used when documentation lacks the detail needed for a more specific code. An exclusive note indicating two conditions cannot coexist and both cannot be coded simultaneously. A note indicating the excluded condition is not part of the coded condition, but both may be coded if clinically present. The character 'X' inserted in an empty position within a code to allow a required seventh character to maintain its correct position. A coding convention requiring the underlying disease (etiology) to be coded first, followed by the resulting condition (manifestation). The portion of ICD-10-CM organized alphabetically by condition/main term; the required starting point for code lookup. The numerical listing of all ICD-10-CM codes organized by chapter; the final authority for code selection. A code characteristic that specifies whether a condition affects the right side, left side, or both sides of the body. An optional or required additional character providing information such as encounter type (initial, subsequent, sequela) or fetal identification. Words in parentheses in the Alphabetic Index that may or may not be present in documentation without affecting code assignment. In inpatient settings, the condition established after study to be chiefly responsible for occasioning the admission. A four-, five-, or six-character code providing greater specificity than the three-character category.