Not every CARC 97 denial should be appealed, but when two services on the same claim were genuinely separate and distinct, you have a real case. The key is understanding when bundling is clinically appropriate and when it is not, and then assembling the documentation to prove your position.
Check the CCI edit first
Before writing a single word of an appeal, look up the two codes in the CMS National Correct Coding Initiative (NCCI) edit table. You need to know one thing: what is the modifier indicator for this code pair?
- Modifier indicator "1": the bundling edit CAN be overridden with an appropriate modifier. Your appeal is viable — continue.
- Modifier indicator "0": the bundling edit CANNOT be overridden by any modifier. This is an absolute bundle. Do not appeal; the denial is correct. Write it off.
NCCI edits are searchable at the CMS website under the National Correct Coding Initiative section. If your practice management system includes a CCI checker, use it.
Choosing the right modifier
When the modifier indicator is "1," you have modifier options. Modifier 59 is the general unbundling modifier, but CMS has defined four more specific X-modifiers that are preferred when they apply:
| Modifier | When to use |
|---|---|
| XE | Separate encounter: services performed during a separate patient encounter on the same date |
| XS | Separate structure: services performed on a separate organ or anatomical structure |
| XP | Separate practitioner: services performed by a different practitioner |
| XU | Unusual non-overlapping service: the service does not overlap with the usual components of the primary procedure |
| 59 | Use when none of the X-modifiers precisely apply but the services are genuinely distinct |
Using the most specific modifier strengthens your appeal. A payer who sees XS with anatomical documentation is more likely to approve than a generic 59 without specifics.
Documentation required
The modifier alone will not win the appeal; the documentation has to back it up. For each X-modifier, here is what you need:
- XE (separate encounter): two separate progress notes or encounter records showing distinct patient encounters, different times, different clinical purposes
- XS (separate structure): operative report or clinical notes clearly identifying the different anatomical locations — "right knee" and "left shoulder," for example
- XP (separate practitioner): documentation of the different rendering providers for each service
- 59/XU: clinical notes explaining why the component service goes beyond the usual components of the primary procedure
Writing the appeal
Structure the appeal letter around the seven-part anatomy from the master appeal guide. Every part matters, and the specifics for this denial are below.
Provider and practice information
Open with the identifiers the payer needs to locate the claim.
- Provider's full name and credentials
- Practice or facility name, NPI, and Tax ID
- Provider's NPI and Tax ID
- Contact information
Always include this on your office letterhead.
Accurate patient and claim details
- Patient name, DOB, and member ID
- Claim number, dates of service, and the original denial date
- CPT/HCPCS and ICD codes
These are what payer staff use to locate the claim. The member ID is the identifier they reach for first.
Denial reference and appeal purpose
State the exact CARC code and any RARC codes (not every denial includes one). Quote the payer's stated denial reason verbatim from the EOB or ERA. Do not risk getting the appeal denied before the supporting documentation is even reviewed by arguing the wrong denial reason.
Coding and policy argument
This needs to be grounded in facts. Explain why the denial is incorrect. Structure your appeal letter around the clinical documentation for clinical denials. For policy disputes, contract disputes, or fee schedule disagreements, structure your appeal letter to refer to those policies or agreements. Name the specific policy or contract term, and state why and how the policy or contract does not support the denial. For Medicare claims, cite the applicable LCD or NCD.
Supporting evidence
Attach numbered exhibits. Clearly identify each item:
- The EOB or remittance advice showing the denial
- Progress notes or operative reports
- Prior auth confirmations
- Clearinghouse batch transmission report with timestamp
- AMA CPT coding guidelines
- The payer's own medical policy
Explicit request for reconsideration
Clearly state what you are requesting: reconsideration, reprocessing, or payment at the contracted rate. Vague phrases like "please review" give the payer room to close the appeal without action.
Signature and credentials
Sign with a named person's full name, credentials, NPI where applicable, and direct contact information. For medical-necessity appeals, a clinician's signature carries the most weight. A named, reachable signer makes follow-up easier and signals the appeal was reviewed by someone accountable.
Bundling appeal letter template
Download the fillable Word template. Every bracketed field is a click-and-type control, so you can complete the letter, edit anything you need, and save it onto your own letterhead. Structured for CARC 97 and 204 denials, with the modifier 59 / X-modifier framework and the NCCI edit documentation checklist built in.
Download the Word template