# CARC 204 Denial Code (Service / Drug Not Covered Under Patient Benefit Plan) | ANSI 835 EDI Spec
> Comprehensive healthcare EDI technical reference and denial resolution guide for Claim Adjustment Reason Code 204 (Service / Drug Not Covered Under Patient Benefit Plan) under ANSI ASC X12 835 005010X221A1.

- **Canonical URL:** https://stanzaapi.com/tools/x12-parser/carc/carc-204-not-covered-benefit-plan
- **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) 204 communicates: "This service/equipment/drug is not covered under the patient's current benefit plan.".

In ANSI X12 835 Electronic Remittance Advice (ERA) files, CARC 204 is reported in Loop 2110 (Service Payment Information) or Loop 2100 (Claim Payment Information) under the Claim Adjustment (CAS) segment with Group Code 'PR' (Patient Responsibility), formatted as: CAS*PR*204*AMOUNT~.

Root Cause: Specific exclusion in subscriber employer group benefit package.

Adjudication & Appeal Strategy: Verify benefit plan details; invoice patient as non-covered balance if patient agreed in financial agreement.

## Specification Matrix
| Attribute | Value | Technical Guidance |
| --- | --- | --- |
| Reason Code | CARC 204 | Service / Drug Not Covered Under Patient Benefit Plan |
| Standard Group Code | PR | Patient Responsibility |
| ANSI 835 Segment | CAS*PR*204*AMOUNT~ | Loop 2110 or Loop 2100 |
| Balance Billing Patient | Allowed as patient responsibility. | Compliance with billing regulations |
| Common RARCs | N386 | Remittance Advice Remark Codes |
| Recommended Action | Verify benefit plan details; invoice patient as non-covered balance if patient agreed in financial agreement. | Workflow for billing teams |

## Standard JSON Response Model
```json
{
  "transactionType": "835",
  "claimNumber": "CLM-2026-001",
  "adjudication": {
    "billedAmount": 500,
    "paidAmount": 0,
    "adjustments": [
      {
        "groupCode": "PR",
        "groupName": "Patient Responsibility",
        "reasonCode": "204",
        "reasonDescription": "Service / Drug Not Covered Under Patient Benefit Plan",
        "adjustmentAmount": 500
      }
    ]
  }
}
```

## Frequently Asked Questions & Edge Cases
### Q: What does CARC 204 mean on an 835 ERA?
**A:** CARC 204 signifies: "This service/equipment/drug is not covered under the patient's current benefit plan.". It explains why the payer did not pay the full billed charge.

### Q: Can a provider balance-bill the patient for CARC 204?
**A:** Allowed as patient responsibility.

### Q: How do medical billing teams resolve and appeal CARC 204?
**A:** Verify benefit plan details; invoice patient as non-covered balance if patient agreed in financial agreement.