Mutually exclusive codes. According to NCCI, mutually exclusive codes are those that should not be billed together due to conflicting CPT definitions or "the medical impossibility/improbability that the procedures could be performed at the same session." Although these codes technically are not bundled, they should not typically be reported on a single claim. When you report codes identified as mutually exclusive for a single surgical session, usually the carrier will recognize and reimburse only the lesser-valued procedure.
For example, if a urologist performs a ureterocolon conduit (50815, Ureterocolon conduit, including intestine anastomosis) he would not also perform a ureteroileal conduit (50820, Ureteroileal conduit [ileal bladder], including intestine anastomosis [Bricker operation]) at the same surgical session.
In another example, if a urologist performs a subsequent male urethral dilation (53601*, Dilation of urethral stricture by passage of sound or urethral dilator, male; subsequent), he could not possibly perform and bill for an initial male urethral dilation (53600*, Dilation of urethral stricture by passage of sound or urethral dilator, male; initial) at the same surgical session.
Bundled codes. A bundle is the commonly used term to describe a pair of codes, one of which represents the comprehensive code and the other represents the component code. NCCI considers the service represented by the component code included in and not separately billable from the service represented by the comprehensive code. NCCI outlines the rationale for bundling component codes into comprehensive codes:
These three codes are component codes bundled into the comprehensive procedure (50575) and, as such, are not separately chargeable.