835 Denial Combination
CO-236+N519
Contractual Obligation · Claim + Service Level Adjustment
Coding ErrorWhat This Combination Means
The claim contains procedures billed with an invalid combination of HCPCS modifiers that violates National Correct Coding Initiative (NCCI) edits or state fee schedule rules for same-day services. The payer has identified that the specific modifiers applied to the procedure codes cannot be used together, resulting in a coding error that prevents proper adjudication. This is a contractual adjustment that must be written off by the provider.
Financial Responsibility
provider writeoff
The provider must write off the denied amount as a contractual obligation. The patient cannot be billed for this adjustment because it results from the provider's improper use of modifier combinations.
N/A
Appeal Success
Corrected claim resubmission (7-14 days)
Avg. Resolution
Medium
Difficulty
No
Appealable
Step-by-Step Resolution
Steps tailored specifically to this CO-236+N519 combination — not generic advice.
- 1
Compare the billed HCPCS modifiers against NCCI edits or payer-specific modifier combination rules
Identify which specific modifier pairing on the same-day procedures triggered the N519 invalid combination flag
- 2
Determine the correct modifier sequence or remove incompatible modifiers based on clinical documentation
Apply appropriate modifiers that accurately reflect the service performed without violating NCCI or payer modifier combination edits
- 3
Submit a corrected claim with the valid modifier combination
Use corrected claim submission process (Claim Frequency Code 7) to replace the original claim with proper modifier usage
Specialty Context
How CO-236+N519 typically presents across different practice types.
Dental
Medical
Common in surgical specialties when billing multiple procedures on the same day with modifiers 59, 51, RT, LT, or anatomical modifiers that conflict with NCCI Column 1/Column 2 edits or modifier sequencing rules
Behavioral Health
May occur when billing multiple therapy codes (e.g., psychotherapy with E/M) on the same day with incompatible modifier combinations such as 25 and 59 applied incorrectly
Individual Code References
View the standalone definition for each code in this combination.
Medicare Contractor Guidance for CARC 236
FCSO + uhc + aetna + bcbs_azThis 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. This denial is received when the service(s) has/have already been paid as part of another service billed for the same date of service.
How to Prevent CARC 236 Denials
- ✓
If an NCCI associated modifier is clinically appropriate, apply the appropriate modifier to the minor/column 2 code only. Effective with date of service July 1, 2019, modifier 59 or subsets may be applied to either the major or minor code for Part B services only.
- ✓
Refer to the modifier policy indicator column in the PTP edit tables: 0=modifier not allowed, 1=modifier is allowed, 9=not applicable.
- ✓
Never append a modifier to solely bypass an NCCI PTP edit.
- ✓
Validate for the appropriate procedure/modifier combination via the Modifier lookup tool.
- ✓
Procedures are to be reported with the most comprehensive code.
- ✓
Stay up to date with the quarterly CMS updates on NCCI page.
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