ICD-Tip: What is CMS definition of " Family of Codes"?Family of codes is the sames as the ICD-10 three character category. Codes with a category are clinically related and provided differences in capturing specific information on the type of the condition. For instance, category H25 (age related cataract) contains a number of specific codes that capture information on the type of cataract as well as information on the eye involved.