Coding Conventions

Next, let's review 7th character, abbreviations, punctuation, and more coding conventions used in ICD-10-CM.

7th Character

Certain ICD-10-CM categories have applicable 7th characters. You must use the applicable 7th character for all ICD-10-CM codes within the category or as notes in the Tabular List instruct.

The meanings of the 7th character can differ across chapters and categories. Like in the External Cause of Injuries chapters, it identifies an initial encounter, subsequent encounter, or sequela late effect.

The 7th character must always be the 7th character in the data field. When it applies, codes missing this character are invalid. We’ll discuss more about placeholder character X in Lesson 2.