CARC 4 Denial Code (Procedure Code Inconsistent with Modifier Used) | ANSI 835 EDI Spec
Comprehensive healthcare EDI technical reference and denial resolution guide for Claim Adjustment Reason Code 4 (Procedure Code Inconsistent with Modifier Used) under ANSI ASC X12 835 005010X221A1. This specification documents the exact field layout, checksum rules, and validation behavior so your integration matches ANSI ASC X12 Standards (005010) without reading the source standard.
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Quick Summary: Comprehensive healthcare EDI technical reference and denial resolution guide for Claim Adjustment Reason Code 4 (Procedure Code Inconsistent with Modifier Used) under ANSI ASC X12 835 005010X221A1. Validates strictly against ANSI ASC X12 Standards (005010) with sub-5ms in-memory response times.
Specification & Structural Breakdown
Technical Summary: Validates strictly against ANSI ASC X12 Standards (005010). Payloads are parsed in memory and return clean, typed JSON in milliseconds with zero data logged.
Claim Adjustment Reason Code (CARC) 4 communicates: "The procedure code is inconsistent with the modifier used or a required modifier is missing.".
In ANSI X12 835 Electronic Remittance Advice (ERA) files, CARC 4 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*4*AMOUNT~.
Root Cause: Incompatible CPT/HCPCS modifier (e.g., billing bilateral modifier 50 on a code that already includes bilateral services, or missing modifier 25 on E/M with procedure).
Adjudication & Appeal Strategy: Review CPT modifier rules, remove invalid modifier or append missing anatomical/informational modifier, and submit corrected claim.
| Attribute | Value | Technical Guidance |
|---|---|---|
| Reason Code | CARC 4 | Procedure Code Inconsistent with Modifier Used |
| Standard Group Code | CO | Contractual Obligation |
| ANSI 835 Segment | CAS*CO*4*AMOUNT~ | Loop 2110 or Loop 2100 |
| Balance Billing Patient | Prohibited. | Compliance with billing regulations |
| Common RARCs | M20, N519 | Remittance Advice Remark Codes |
| Recommended Action | Review CPT modifier rules, remove invalid modifier or append missing anatomical/informational modifier, and submit corrected claim. | Workflow for billing teams |
Parsed JSON Response Model
The edge microservice transforms input payloads into strongly-typed hierarchical JSON envelopes with sub-5ms latency:
{
"transactionType": "835",
"claimNumber": "CLM-2026-001",
"adjudication": {
"billedAmount": 500,
"paidAmount": 0,
"adjustments": [
{
"groupCode": "CO",
"groupName": "Contractual Obligation",
"reasonCode": "4",
"reasonDescription": "Procedure Code Inconsistent with Modifier Used",
"adjustmentAmount": 500
}
]
}
}
Copy-Paste Integration Code (6 Languages)
Integrate CARC 4 Denial Code (Procedure Code Inconsistent with Modifier Used) | ANSI 835 EDI Spec directly into your production application with native, zero-dependency code snippets in cURL, Node.js, Python, Go, C#, and a ready-to-paste Claude prompt. Get a free API key → (no credit card required):
curl --request POST \
--url "https://api.stanzaapi.com/x12-parser/api/v1/x12/parse" \
--header "Content-Type: application/json" \
--header "x-api-key: YOUR_API_KEY" \
--data '{
"raw": "ISA*00* *00* *ZZ*SUBMITTER1 *ZZ*RECEIVER01 *260830*1200*^*00501*000000001*0*P*:~GS*HC*SENDER*RECEIVER*20260830*1200*1*X*005010X222A1~ST*837*0001*005010X222A1~BHT*0019*00*CLAIM001*20260830*1200*CH~NM1*41*2*DR DOE CLINIC*****46*1234567890~PER*IC*SUPPORT*TE*8005551212~HL*1**20*1~NM1*85*2*DR DOE CLINIC*****XX*1992837465~HL*2*1*22*0~NM1*IL*1*SMITH*JANE****MI*W123456780~CLM*CLM001*150.00***11::1*Y*A*Y*Y~LX*1~SV1*HC:99213*150.00*UN*1***1~SE*11*0001~GE*1*1~IEA*1*000000001~"
}'const response = await fetch("https://api.stanzaapi.com/x12-parser/api/v1/x12/parse", {
method: "POST",
headers: {
"Content-Type": "application/json",
"x-api-key": process.env.API_KEY || "YOUR_API_KEY"
},
body: JSON.stringify({
"raw": "ISA*00* *00* *ZZ*SUBMITTER1 *ZZ*RECEIVER01 *260830*1200*^*00501*000000001*0*P*:~GS*HC*SENDER*RECEIVER*20260830*1200*1*X*005010X222A1~ST*837*0001*005010X222A1~BHT*0019*00*CLAIM001*20260830*1200*CH~NM1*41*2*DR DOE CLINIC*****46*1234567890~PER*IC*SUPPORT*TE*8005551212~HL*1**20*1~NM1*85*2*DR DOE CLINIC*****XX*1992837465~HL*2*1*22*0~NM1*IL*1*SMITH*JANE****MI*W123456780~CLM*CLM001*150.00***11::1*Y*A*Y*Y~LX*1~SV1*HC:99213*150.00*UN*1***1~SE*11*0001~GE*1*1~IEA*1*000000001~"
})
});
const data = await response.json();
console.log(data);import requests
import json
url = "https://api.stanzaapi.com/x12-parser/api/v1/x12/parse"
headers = {
"Content-Type": "application/json",
"x-api-key": "YOUR_API_KEY"
}
payload = {
"raw": "ISA*00* *00* *ZZ*SUBMITTER1 *ZZ*RECEIVER01 *260830*1200*^*00501*000000001*0*P*:~GS*HC*SENDER*RECEIVER*20260830*1200*1*X*005010X222A1~ST*837*0001*005010X222A1~BHT*0019*00*CLAIM001*20260830*1200*CH~NM1*41*2*DR DOE CLINIC*****46*1234567890~PER*IC*SUPPORT*TE*8005551212~HL*1**20*1~NM1*85*2*DR DOE CLINIC*****XX*1992837465~HL*2*1*22*0~NM1*IL*1*SMITH*JANE****MI*W123456780~CLM*CLM001*150.00***11::1*Y*A*Y*Y~LX*1~SV1*HC:99213*150.00*UN*1***1~SE*11*0001~GE*1*1~IEA*1*000000001~"
}
response = requests.post(url, json=payload, headers=headers)
print(response.json())package main
import (
"bytes"
"fmt"
"io"
"net/http"
"os"
)
func main() {
url := "https://api.stanzaapi.com/x12-parser/api/v1/x12/parse"
payload := []byte(`{"raw":"ISA*00* *00* *ZZ*SUBMITTER1 *ZZ*RECEIVER01 *260830*1200*^*00501*000000001*0*P*:~GS*HC*SENDER*RECEIVER*20260830*1200*1*X*005010X222A1~ST*837*0001*005010X222A1~BHT*0019*00*CLAIM001*20260830*1200*CH~NM1*41*2*DR DOE CLINIC*****46*1234567890~PER*IC*SUPPORT*TE*8005551212~HL*1**20*1~NM1*85*2*DR DOE CLINIC*****XX*1992837465~HL*2*1*22*0~NM1*IL*1*SMITH*JANE****MI*W123456780~CLM*CLM001*150.00***11::1*Y*A*Y*Y~LX*1~SV1*HC:99213*150.00*UN*1***1~SE*11*0001~GE*1*1~IEA*1*000000001~"}`)
req, _ := http.NewRequest("POST", url, bytes.NewBuffer(payload))
req.Header.Add("Content-Type", "application/json")
req.Header.Add("x-api-key", os.Getenv("API_KEY"))
res, err := http.DefaultClient.Do(req)
if err != nil {
panic(err)
}
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))
}using System;
using System.Net.Http;
using System.Text;
using System.Threading.Tasks;
class Program
{
static async Task Main()
{
using var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", Environment.GetEnvironmentVariable("API_KEY") ?? "YOUR_API_KEY");
var json = @"{""raw"":""ISA*00* *00* *ZZ*SUBMITTER1 *ZZ*RECEIVER01 *260830*1200*^*00501*000000001*0*P*:~GS*HC*SENDER*RECEIVER*20260830*1200*1*X*005010X222A1~ST*837*0001*005010X222A1~BHT*0019*00*CLAIM001*20260830*1200*CH~NM1*41*2*DR DOE CLINIC*****46*1234567890~PER*IC*SUPPORT*TE*8005551212~HL*1**20*1~NM1*85*2*DR DOE CLINIC*****XX*1992837465~HL*2*1*22*0~NM1*IL*1*SMITH*JANE****MI*W123456780~CLM*CLM001*150.00***11::1*Y*A*Y*Y~LX*1~SV1*HC:99213*150.00*UN*1***1~SE*11*0001~GE*1*1~IEA*1*000000001~""}";
var payload = new StringContent(json, Encoding.UTF8, "application/json");
var response = await client.PostAsync("https://api.stanzaapi.com/x12-parser/api/v1/x12/parse", payload);
var content = await response.Content.ReadAsStringAsync();
Console.WriteLine(content);
}
}Integrate the StanzaAPI x12-parser micro-API.
Endpoint: POST https://api.stanzaapi.com/x12-parser/api/v1/x12/parse
Auth header: x-api-key: YOUR_API_KEY
Content-Type: application/json
Request body:
{
"raw": "ISA*00* *00* *ZZ*SUBMITTER1 *ZZ*RECEIVER01 *260830*1200*^*00501*000000001*0*P*:~GS*HC*SENDER*RECEIVER*20260830*1200*1*X*005010X222A1~ST*837*0001*005010X222A1~BHT*0019*00*CLAIM001*20260830*1200*CH~NM1*41*2*DR DOE CLINIC*****46*1234567890~PER*IC*SUPPORT*TE*8005551212~HL*1**20*1~NM1*85*2*DR DOE CLINIC*****XX*1992837465~HL*2*1*22*0~NM1*IL*1*SMITH*JANE****MI*W123456780~CLM*CLM001*150.00***11::1*Y*A*Y*Y~LX*1~SV1*HC:99213*150.00*UN*1***1~SE*11*0001~GE*1*1~IEA*1*000000001~"
}
Rules:
- Send the request with a 2-second timeout.
- Parse the standard envelope { success, data, meta: { latency_ms, version } }.
- On failure, read { success: false, error, code } and branch on the code.
- Do not retry 4xx responses; surface the error code to the caller.
- Treat invalid-but-well-formed payloads as HTTP 200 with data.valid === false.Frequently Asked Questions & Technical Notes
CARC 4 signifies: "The procedure code is inconsistent with the modifier used or a required modifier is missing.". It explains why the payer did not pay the full billed charge.
Prohibited.
Review CPT modifier rules, remove invalid modifier or append missing anatomical/informational modifier, and submit corrected claim.
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