Modifier 59: Distinct procedural service

When it is appropriate

Append modifier 59 to the column two code of an NCCI pair when the two procedures were truly distinct, for example a different session or patient encounter, a different procedure, a different anatomic site or organ system, a separate incision or excision, or a separate lesion, and no more specific modifier describes the distinction. It should only be used when the medical record clearly documents that the services were not part of the same procedural work.

When it is not appropriate

Do not use 59 simply because a claim was denied for bundling, or to separate two components of what is really a single procedure. Routinely appending 59 to force payment on codes that are normally bundled, without a genuine and documented clinical reason, is the pattern auditors look for.

CMS preference

Use the specific X modifier (XE, XS, XP, XU) instead of 59 whenever one of them precisely describes the reason the services are distinct; reserve 59 for situations none of the X modifiers capture.

Denial codes that point at this modifier

The corrective actions we publish for these CARCs name modifier 59. Read the denial first: the modifier only helps where the edit and the documentation both support it.

• CO-97The benefit for this service is included in the payment/allowance for another service/procedure that has already been adjudicated.
• CO-4The procedure code is inconsistent with the modifier used.
• CO-236This procedure or procedure/modifier combination is not compatible with another procedure or procedure/modifier combination provided on the same day according to the National Correct Coding Initiative or workers compensation state regulations/fee schedule requirements.
• CO-59Processed based on multiple or concurrent procedure rules.