What function do parentheses serve in ICD-10-CM codes?

In ICD-10-CM codes, parentheses are used to enclose supplementary words or explanatory information that do not affect the code's selection. They help clarify the meaning of a code or its classification without adding to the requirements of what the code signifies. This additional information can include terms that provide context, such as descriptions or variations of the main term, which are essential for understanding the specificity of the diagnosis but do not change the code itself.

For instance, within a specific code, you might find terms in parentheses that clarify particular aspects or examples of the condition. This allows coders and practitioners to better understand the code's application without altering the core definition of the diagnosis assigned. In contrast, the other options indicate functions that do not align with the role that parentheses actually fulfill within the coding system.