# CARC 11 Denial Code (Diagnosis Inconsistent with Procedure) | ANSI 835 EDI Spec
> Comprehensive healthcare EDI technical reference and denial resolution guide for Claim Adjustment Reason Code 11 (Diagnosis Inconsistent with Procedure) under ANSI ASC X12 835 005010X221A1.

- **Canonical URL:** https://stanzaapi.com/tools/x12-parser/carc/carc-11-diagnosis-inconsistent
- **Governing Standard:** ANSI ASC X12 Standards (005010) (Accredited Standards Committee X12 / HIPAA 5010)
- **Edge Latency SLA:** <2ms Edge (Cloudflare V8 Isolates)
- **Execution Model:** Pure compute $f(x) = y$, 100% In-Memory (Zero Store, Zero Log)

## Technical Overview & Governing Rules
Claim Adjustment Reason Code (CARC) 11 communicates: "The diagnosis is inconsistent with the procedure.".

In ANSI X12 835 Electronic Remittance Advice (ERA) files, CARC 11 is reported in Loop 2110 (Service Payment Information) or Loop 2100 (Claim Payment Information) under the Claim Adjustment (CAS) segment with Group Code 'CO' (Contractual Obligation), formatted as: CAS*CO*11*AMOUNT~.

Root Cause: ICD-10-CM diagnosis code billed in Loop 2300 HI segment does not establish medical necessity for CPT code under payer LCD/NCD coverage policies.

Adjudication & Appeal Strategy: Review medical records to confirm if secondary diagnosis that supports the procedure was documented; update diagnosis pointer in SV107 and resubmit.

## Specification Matrix
| Attribute | Value | Technical Guidance |
| --- | --- | --- |
| Reason Code | CARC 11 | Diagnosis Inconsistent with Procedure |
| Standard Group Code | CO | Contractual Obligation |
| ANSI 835 Segment | CAS*CO*11*AMOUNT~ | Loop 2110 or Loop 2100 |
| Balance Billing Patient | Prohibited. | Compliance with billing regulations |
| Common RARCs | M64, N381 | Remittance Advice Remark Codes |
| Recommended Action | Review medical records to confirm if secondary diagnosis that supports the procedure was documented; update diagnosis pointer in SV107 and resubmit. | Workflow for billing teams |

## Standard JSON Response Model
```json
{
  "transactionType": "835",
  "claimNumber": "CLM-2026-001",
  "adjudication": {
    "billedAmount": 500,
    "paidAmount": 0,
    "adjustments": [
      {
        "groupCode": "CO",
        "groupName": "Contractual Obligation",
        "reasonCode": "11",
        "reasonDescription": "Diagnosis Inconsistent with Procedure",
        "adjustmentAmount": 500
      }
    ]
  }
}
```

## Frequently Asked Questions & Edge Cases
### Q: What does CARC 11 mean on an 835 ERA?
**A:** CARC 11 signifies: "The diagnosis is inconsistent with the procedure.". It explains why the payer did not pay the full billed charge.

### Q: Can a provider balance-bill the patient for CARC 11?
**A:** Prohibited.

### Q: How do medical billing teams resolve and appeal CARC 11?
**A:** Review medical records to confirm if secondary diagnosis that supports the procedure was documented; update diagnosis pointer in SV107 and resubmit.