What Is A Subcategory In ICD-10?

What Is A Subcategory In ICD-10? Subcategory. In ICD codes, the subcategory describes the digit that comes after the decimal point. This digit further describes the nature of the illness or injury, and gives additional information as to its location or manifestation. How do you code subacute? Answer: Assign code 45.39, acute venous embolism and