Understanding Subterms in ICD-9-CM Coding

What Are Subterms?

In ICD-9-CM, subterms add specificity to a main code—typically site, laterality, or procedure type. They appear in parentheses after the code.

Examples

• 812.11 (L) – Fracture of humeral shaft, left arm.
• 944.20 (face and neck) – Burn of face and neck.
• 47.0 (laparoscopic) – Laparoscopic appendectomy.

Importance

Subterms ensure accurate representation of clinical detail, supporting proper reimbursement, epidemiology, and care planning.

Note: ICD-9-CM was replaced by ICD-10-CM in the U.S. (2015), which uses a different alphanumeric structure with built-in laterality and specificity.