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CO-B22 Denial Code: Payment Adjusted Based on Diagnosis

CO-B22 means the payer adjusted the payment because of the diagnosis on the claim. The diagnosis affected how the service was priced or covered, for example by triggering a different benefit, a limit, or a reduced rate.

Quick facts

Code
CO-B22 (CARC B22)
Status
Active In use since January 1, 1995; last modified February 28, 2001.
Code set
Claim Adjustment Reason Codes (CARC)
Group codes
  • CO (Contractual Obligation): The usual group. The provider absorbs the adjustment and can't bill the patient for it.
  • PR (Patient Responsibility): Used when the diagnosis moved the service into a benefit where the patient owes more. The patient may be billed for the PR amount.
Official description
This payment is adjusted based on the diagnosis.
X12 Claim Adjustment Reason Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What CO-B22 means

CARC B22 says this payment is adjusted based on the diagnosis. The payer didn’t necessarily deny the service; it priced or covered it differently because of the ICD-10-CM codes on the claim. The adjustment could be a reduction, a shift to a different benefit, or a limit tied to the condition.

Diagnosis can affect payment in several ways:

  • Benefit category. A screening diagnosis may place a test under preventive benefits, while a symptom diagnosis places it under diagnostic benefits with different cost-sharing.
  • Carve-outs. Behavioral health diagnoses may be paid under a separate benefit or vendor.
  • Coverage limits tied to specific conditions.
  • Accident or injury indicators, which may trigger coordination with other coverage.

Common causes

  • Wrong primary diagnosis listed first in box 21.
  • Diagnosis pointer errors in box 24E linking the line to the wrong condition.
  • Screening versus diagnostic confusion, especially for labs, imaging, and preventive services.
  • Non-specific diagnosis codes that fall under a lower-paying or limited benefit.
  • Diagnosis-based fee schedules in some Medicaid or specialty programs.

How to fix it

  1. Identify how the diagnosis affected payment using the remark codes, policy references, or a call to the payer.
  2. Review the record to confirm the diagnoses and their order.
  3. If coding or pointers were wrong, correct them and send a corrected claim with resubmission code 7 in box 22.
  4. If the coding was correct, check the adjustment against your contract and the payer’s policy, and request reconsideration if it doesn’t match.
  5. Bill the patient only for amounts reported as PR.

How to prevent it

  • Code the primary reason for the visit first, supported by documentation.
  • Link each line to its supporting diagnosis.
  • Train staff on screening versus diagnostic coding.
  • Check diagnosis-driven rules before submission. A Claims Validator can flag lines pointing to diagnoses that commonly change payment.

Specialty notes

Integrated primary care and behavioral health practices should watch for CO-B22 when a mental health diagnosis moves a service into a carved-out behavioral health benefit.

Remark codes that may appear with CO-B22

  • M76 (Missing/incomplete/invalid diagnosis or condition.): The diagnosis is missing, incomplete, or invalid.
  • N115 (This decision was based on a Local Coverage Determination (LCD).): The decision was based on a Local Coverage Determination tied to diagnoses.
  • N130 (Consult plan benefit documents/guidelines for information about restrictions for this service.): Directs you to plan documents describing diagnosis-based benefits.
  • CO-11 (The diagnosis is inconsistent with the procedure.): The diagnosis is inconsistent with the procedure, usually a full denial.
  • CO-167 (This (these) diagnosis(es) is (are) not covered.): The diagnosis isn't covered at all.
  • CO-146 (Diagnosis was invalid for the date(s) of service reported.): The diagnosis was invalid for the date of service.
  • CO-50 (These are non-covered services because this is not deemed a 'medical necessity' by the payer.): Medical necessity denial.

CO-B22 FAQ

How can a diagnosis change payment?

Some plans apply different benefits, cost-sharing, or rates depending on diagnosis, for example preventive versus diagnostic care, behavioral health versus medical benefits, or accident-related care.

What should I check after CO-B22?

Check that the diagnoses in box 21 match the documentation and that each line points to the right diagnosis in box 24E. Also confirm the primary diagnosis reflects the main reason for the service.

Can I change the diagnosis to get paid more?

Only if the documentation supports a different diagnosis or order. Codes must always reflect what the provider documented.

Is CO-B22 a denial?

Not always. It can be a partial reduction rather than a full denial. Compare the payment to what you expected under the correct diagnosis.

Does CO-B22 affect the patient's balance?

It can. If the diagnosis moved the service into a benefit with different cost-sharing, the patient responsibility on the ERA may change too. Post the PR amounts exactly as reported.