A seventh character has been added to some chapters of ICD-10-CM. The meanings of the seventh character vary across chapters and categories, though. The language of each applicable ICD-10-CM category will identify the necessity to use a seventh character. The applicable seventh character is required for all codes within certain categories, or as the notes in the tabular lists instruct. A code that has an applicable seventh character is considered invalid without the seventh character. Such characters also always must be the seventh characters in the data field, and if the code is not of sufficient length, a placeholder of “x” is required to fill empty characters.