# CARC 45 Denial Code (Charge Exceeds Fee Schedule / Maximum Allowable Amount) | ANSI 835 EDI Spec
> Comprehensive healthcare EDI technical reference and denial resolution guide for Claim Adjustment Reason Code 45 (Charge Exceeds Fee Schedule / Maximum Allowable Amount) under ANSI ASC X12 835 005010X221A1.

- **Canonical URL:** https://stanzaapi.com/tools/x12-parser/carc/carc-45-charge-exceeds-fee-schedule
- **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) 45 communicates: "Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.".

In ANSI X12 835 Electronic Remittance Advice (ERA) files, CARC 45 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*45*AMOUNT~.

Root Cause: The billed charge on the service line exceeds the contracted reimbursement ceiling agreed upon between the participating provider and payer.

Adjudication & Appeal Strategy: Apply contractual write-off in practice management/billing system. In-network providers are legally and contractually obligated not to bill the patient.

## Specification Matrix
| Attribute | Value | Technical Guidance |
| --- | --- | --- |
| Reason Code | CARC 45 | Charge Exceeds Fee Schedule / Maximum Allowable Amount |
| Standard Group Code | CO | Contractual Obligation |
| ANSI 835 Segment | CAS*CO*45*AMOUNT~ | Loop 2110 or Loop 2100 |
| Balance Billing Patient | Strictly Prohibited for participating providers. | Compliance with billing regulations |
| Common RARCs | N517, MA01 | Remittance Advice Remark Codes |
| Recommended Action | Apply contractual write-off in practice management/billing system. In-network providers are legally and contractually obligated not to bill the patient. | 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": "45",
        "reasonDescription": "Charge Exceeds Fee Schedule / Maximum Allowable Amount",
        "adjustmentAmount": 500
      }
    ]
  }
}
```

## Frequently Asked Questions & Edge Cases
### Q: What does CARC 45 mean on an 835 ERA?
**A:** CARC 45 signifies: "Charge exceeds fee schedule/maximum allowable or contracted/legislated fee arrangement.". It explains why the payer did not pay the full billed charge.

### Q: Can a provider balance-bill the patient for CARC 45?
**A:** Strictly Prohibited for participating providers.

### Q: How do medical billing teams resolve and appeal CARC 45?
**A:** Apply contractual write-off in practice management/billing system. In-network providers are legally and contractually obligated not to bill the patient.