CARC B22 Active

CO-B22: Payment Adjusted Based on Diagnosis

TL;DR

CO-B22 means the diagnosis does not support the procedure. Correct the coding or appeal with clinical documentation showing medical necessity.

Action

Resubmit

Who Pays

Provider

Appeal

Yes

Patient Impact

None

Disclaimer

This content is for informational purposes only and does not constitute professional billing advice. Always verify information against your payer contracts and current coding guidelines. Consult a certified billing specialist for specific claim issues.

What Does CO-B22 Mean?

When paired with Group Code CO, the diagnosis-based adjustment is contractual. The provider absorbs the reduction and cannot collect it from the patient. Correct the diagnosis code and resubmit, or appeal with medical necessity documentation.

CARC B22 indicates the payer adjusted the payment based on the diagnosis codes submitted with the claim. The diagnosis either does not support medical necessity for the billed procedure, triggers a lower fee schedule rate, results in a different DRG assignment, or does not appear on the payer's approved diagnosis list for the service (LCD/NCD).

This is one of the most common coding-related adjustments. It frequently occurs when diagnosis codes are too generic or non-specific, when the LCD/NCD restricts coverage of the procedure to specific diagnoses, when the diagnosis-procedure combination does not establish medical necessity, or when incorrect coding causes a DRG weight reduction for inpatient claims.

The resolution path depends on whether the issue is a coding error (wrong or non-specific diagnosis) or a coverage determination (the diagnosis genuinely does not support the procedure). Coding errors can be corrected and resubmitted. Coverage determinations require a clinical appeal with documentation supporting medical necessity.

Common Causes

Cause	Frequency
Diagnosis does not support procedure The diagnosis code submitted does not support medical necessity for the billed procedure according to the payer's medical policy or LCD/NCD	Most Common
Diagnosis-based fee schedule reduction The payer's fee schedule applies a lower allowed amount for the procedure when billed with the submitted diagnosis code	Most Common
DRG payment affected by diagnosis The principal or secondary diagnosis resulted in a lower DRG weight and corresponding lower payment for the inpatient stay	Common
Incorrect or non-specific diagnosis code The diagnosis code is too generic or incorrect, resulting in a lower payment or denial	Common
LCD/NCD limitation The Local or National Coverage Determination restricts coverage of the procedure to specific diagnosis codes, and the submitted code is not on the approved list	Common

How to Resolve

Review diagnosis accuracy Verify codes are correct and specific.
Check LCD/NCD Review coverage criteria for the procedure.
Correct and resubmit Fix incorrect codes and resubmit.
Appeal with documentation If coding is correct, appeal with clinical records showing medical necessity.

Appeal Guide

Appeal with clinical documentation supporting the diagnosis and demonstrating medical necessity for the procedure. Include physician notes, test results, and reference the applicable LCD/NCD showing the diagnosis qualifies for coverage. If the diagnosis was incorrectly coded, correct and resubmit.

Common RARC Pairings

The RARC code tells you exactly what triggered the CO-B22:

RARC	Description
M51	Missing/incomplete/invalid procedure code(s). Verify the diagnosis-procedure compatibility and correct codes if needed →
N130	Alert: You may need to review plan documents or guidelines. Review LCD/NCD for covered diagnoses for the billed procedure →

How to Prevent CO-B22

Code diagnoses to the highest level of specificity supported by the medical record
Verify diagnosis codes against LCD/NCD coverage criteria before submitting claims
Use claims scrubbing tools that check diagnosis-procedure compatibility
Stay current with payer medical policy updates and LCD/NCD changes
Implement Clinical Documentation Improvement (CDI) programs to capture accurate diagnoses

Also Filed As

The same CARC B22 may appear with different Group Codes:

PR-B22 OA-B22

Related Denial Codes

CO-146 — Diagnosis Invalid for Date of Service CO-181 — Procedure Code Invalid on Date of Service CO-182 — Procedure Modifier Invalid on Date of Service CO-16 — Missing Information or Billing Error CO-144 — Incentive Adjustment for Preferred Product/Service

Sources

https://x12.org/codes/claim-adjustment-reason-codes
https://www.cms.gov/regulations-and-guidance/guidance/manuals
Codes maintained by X12. Visit x12.org for official definitions.