Add-on code
An add-on code is a CPT code that supplements a primary procedure and can never be billed or paid on its own.
Updated
An add-on code represents an additional service performed in conjunction with a primary procedure and is reported only in addition to that primary code.
Because add-on codes have no standalone value, claims for them without a qualifying primary code are denied.
In practice
Billers pair add-on codes with the correct primary procedure and verify payer guidance on sequencing, ensuring the primary code is present and supported by documentation.
Commonly confused with
- Primary procedure code: A primary procedure code stands alone for payment; an add-on code depends on a primary code and is not separately reimbursable without it.