835 Denial Combination
CO-252+N433
Contractual Obligation · Claim-Level Adjustment
Missing InformationWhat This Combination Means
The claim was denied because the provider submitted using a non-NPI identifier (such as a legacy UPIN, taxonomy code alone, or state license number) when the payer requires only the National Provider Identifier for adjudication. The missing documentation referenced by CARC 252 is specifically the valid NPI in the appropriate identifier field. Because this is a CO adjustment, the provider cannot bill the patient and must correct the claim submission.
Financial Responsibility
provider writeoff
The provider must write off the denied amount per contractual obligation while the claim is corrected and resubmitted with proper NPI information. Patient cannot be billed for this adjustment.
N/A
Appeal Success
7-14 days (corrected claim processing)
Avg. Resolution
Medium
Difficulty
No
Appealable
Step-by-Step Resolution
Steps tailored specifically to this CO-252+N433 combination — not generic advice.
- 1
Verify the NPI used on the original claim submission
Check whether a non-NPI identifier was submitted in the provider fields (rendering, billing, or referring provider), or if the NPI field was left blank with only legacy identifiers present
- 2
Update claim data to include only valid NPI in all provider identifier fields
Ensure the NPI matches the provider type and service location; remove any legacy identifiers (UPIN, state license) from primary identifier fields if they were used instead of NPI
- 3
Submit a corrected claim with Claim Change Reason Code and proper NPI
Use frequency code 7 (replacement claim) and include the original claim number reference; ensure all provider loops (2310A, 2310B, 2420A-E in 837) contain only NPI values
Specialty Context
How CO-252+N433 typically presents across different practice types.
Dental
Verify that dental provider NPIs (Type 1 for individual dentists, Type 2 for group practices) are correctly distinguished and that taxonomy codes are included in addition to—not instead of—the NPI
Medical
Commonly occurs when legacy practice management systems auto-populate outdated identifier types; verify both rendering and billing provider NPIs are included, especially for facility-based services where multiple provider types are involved
Behavioral Health
Ensure individual therapist/counselor NPIs are used for rendering provider even when billing under a group practice NPI; many behavioral health clearinghouses historically used state license numbers that must now be replaced with NPIs
Individual Code References
View the standalone definition for each code in this combination.
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