Browse all standardized Remark Codes (RARC) used on Medicare, Medicaid, and commercial payer remittance advice (835 ERA / EOB). Each code includes its RA835 mapping, adjustment group, reason code, and a dedicated resolution guide.
Browse Claim Adjustment Reason Codes — the codes that explain why a payment was reduced or denied.
| Remark Code | Description | RA835 Code | Group | Reason Code | |
|---|---|---|---|---|---|
| X432 | Medically High-Risk Diagnosis qualifies for an increase of $10 per visit. | — | CO | B22 | View → |
| X433 | Modifier HM indicates the service should be reimbursed at 75% of the fee schedule. | — | CO | 144 | View → |
| X434 | Modifier is not valid for the state of Indiana. |
N517
Resubmit a new claim with the requested information. |
CO | 182 | View → |
| X435 | Nursing/Home health aid services are limited to 24 units a day. |
N362
The number of Days or Units of Service exceeds our acc… |
CO | 222 | View → |
| X436 | Procedure code on historical claim indicates that multiple services were performed. This line shoul… |
N381
Alert: Consult our contractual agreement for restricti… |
CO | 59 | View → |
| X437 | The first 10 miles of the trip are not payable for CAS and NAS providers. |
N130
Consult plan benefit documents/guidelines for informat… |
CO | 96 | View → |
| X438 | Taxi is not reimbursed for mileage | — | CO | 96 | View → |
| X439 | Time units limited to 6 units when modifier AD is billed. | — | CO | 222 | View → |
| X44 | INSTITUTIONAL CLAIM WAS REGROUPED BASED ON POLICY. FINAL DRG WAS CHANGED . |
N130
Consult plan benefit documents/guidelines for informat… |
CO | 97 | View → |
| X440 | Statutory Adjustment. Payment reduced to of fee payment. |
N381
Alert: Consult our contractual agreement for restricti… |
CO | 144 | View → |
| X441 | Assistant Surgeon modifier indicates the line is reimbursed at 16% of the physician fee schedule. | — | CO | 203 | View → |
| X442 | The presence of modifier 54 indicates that only the Surgical care portion of the global fee should … | — | CO | 203 | View → |
| X443 | The presence of modifier 55 indicates that only Post-operative portion of the global fee should be … | — | CO | 203 | View → |
| X444 | The presence of modifier 56 indicates that only Pre-operative portion of the global fee should be r… | — | CO | 203 | View → |
| X445 | Physician filing for a mid-level provider. Services reimbursed at 92% of fee schedule. | — | CO | 144 | View → |
| X446 | Taxonomy reimburses at a variable percentage of the physician fee schedule. | — | CO | 144 | View → |
| X447 | CRNA service modifier indicates the line is reimbursed at 92% of the physician fee schedule. | — | CO | 144 | View → |
| X448 | (Physician/Ancillary)Per Medicaid's Medically Unlikely Edits Policy, total units billed for procedu… |
M53
Missing/incomplete/invalid days or units of service. |
CO | 222 | View → |
| X449 | (Outpatient)Per Medicaid's Medically Unlikely Edits Policy, total units billed for procedure exceed… |
N362
The number of Days or Units of Service exceeds our acc… |
CO | 222 | View → |
| X45 | INVALID DIAGNOSIS CODE |
M64
Missing/incomplete/invalid other diagnosis. |
CO | 16 | View → |
| X450 | (Physician/Ancillary)Per Medicaid's CCI Guidelines, Procedure Code has an unbundle relationship wit… |
M15
Separately billed services/tests have been bundled as … |
CO | 234 | View → |
| X451 | (Physician/Ancillary)Per Medicaid's CCI Guidelines, History Procedure Code on Claim has an unbundle… |
M15
Separately billed services/tests have been bundled as … |
CO | 234 | View → |
| X452 | (Outpatient)Per Medicaid's CCI Guidelines, Procedure Code has an unbundle relationship with another… |
M15
Separately billed services/tests have been bundled as … |
CO | 234 | View → |
| X453 | (Outpatient)Per Medicaid's CCI Guidelines, History Procedure Code has an unbundle relationship with… |
M15
Separately billed services/tests have been bundled as … |
CO | 234 | View → |
| X454 | LATE BILLS ARE NOT COVERED |
N214
Missing/incomplete/invalid history of the related init… |
CO | B4 | View → |
| X455 | IL MCD emergency contraceptive pills must be billed using J8499 effective with dates of service Jun… |
M119
Missing/incomplete/invalid/ deactivated/withdrawn Nati… |
CO | 16 | View → |
| X456 | FQHC MUST BILL WITH ENCOUNTER CODE T1015 |
N174
This is not a covered service/procedure/ equipment/bed… |
CO | 96 | View → |
| X457 | Type of Bill 13x is invalid for Critical Access Hospital outpatient services. Please rebill using … |
MA30
Missing/incomplete/invalid type of bill. |
CO | 282 | View → |
| X46 | DIAGNOSIS AND AGE CONFLICT |
N517
Resubmit a new claim with the requested information. |
CO | 9 | View → |
| X468 | NDC billed is not in the proper format. The NDC must be in the 5-4-2 configuration. (line level de… |
M119
Missing/incomplete/invalid/ deactivated/withdrawn Nati… |
CO | 16 | View → |
| X469 | NDC billed is not in the proper format. The NDC must be in the 5-4-2 configuration. (claim level d… |
M119
Missing/incomplete/invalid/ deactivated/withdrawn Nati… |
CO | 16 | View → |
| X47 | DIAGNOSIS AND SEX CONFLICT |
N517
Resubmit a new claim with the requested information. |
CO | 10 | View → |
| X471 | Procedure code requires that an NDC must be billed according to NDC billing guidelines. (claim leve… |
N657
This should be billed with the appropriate code for th… |
CO | 16 | View → |
| X472 | S5190 is for reporting purposes only and is not payable. | — | CO | 246 | View → |
| X473 | RENDERING NPI IS NOT VALID FOR THIS ENCOUNTER. |
N570
Missing/incomplete/invalid credentialing data. |
CO | 185 | View → |
| X474 | Place of service is illogical. |
M77
Missing/incomplete/invalid/inappropriate place of serv… |
CO | 16 | View → |
| X475 | Long Acting Reversible Contraception (LARC) must be billed separately from the encounter. |
N130
Consult plan benefit documents/guidelines for informat… |
CO | 96 | View → |
| X48 | MEDICARE SECONDARY PAYER ALERT |
MA64
Our records indicate that we should be the third payer… |
CO | 22 | View → |
| X49 | E-DIAGNOSIS CODE CAN NOT BE USED AS PRINCIPAL DIAGNOSIS |
MA63
Missing/incomplete/invalid principal diagnosis. |
CO | 16 | View → |
| X499 | INSTITUTIONAL CLAIM WAS REGROUPED BASED ON POLICY. FINAL APR-DRG WAS CHANGED. | — | CO | 45 | View → |
| X5 | THE PATIENT SEX IS INVALID |
MA39
Missing/incomplete/invalid gender. |
CO | 7 | View → |
| X50 | INVALID PROCEDURE CODE |
M51
Missing/incomplete/invalid procedure code(s). |
CO | 16 | View → |
| X500 | DIAGNOSTIC/THERAPEUTIC IMAGING RADIOPHARMACEUTICAL / CONTRAST AGENT LINK IS NOT COVERED BY MEDICARE… |
N657
This should be billed with the appropriate code for th… |
CO | 16 | View → |
| X507 | DRUG QUANTITY DISPENSED OR QUANTITY BILLED INFORMATION IS MISSING OR INVALID. |
M123
Missing/incomplete/invalid name, strength, or dosage o… |
CO | 16 | View → |
| X508 | Drug unit qualifier (unit of measure) is missing or invalid |
M123
Missing/incomplete/invalid name, strength, or dosage o… |
CO | 16 | View → |
| X51 | PROCEDURE AND AGE CONFLICT (INACTIVE) |
N129
Not eligible due to the patient's age. |
CO | 6 | View → |
| X517 | Possible improper billing of Accute Kidney Injury claim (Eff. 1/1/2017) |
N657
This should be billed with the appropriate code for th… |
CO | 16 | View → |
| X518 | Revenue code is no longer valid for this service, please rebill with correct H code. |
M50
Missing/incomplete/invalid revenue code(s). |
CO | 16 | View → |
| X519 | Place of service is missing or not valid. |
M77
Missing/incomplete/invalid/inappropriate place of serv… |
CO | 16 | View → |
| X52 | THE PROCEDURE PREFORMED AND THE PATIENT SEX CONFLICT |
M51
Missing/incomplete/invalid procedure code(s). |
CO | 7 | View → |
Remark Codes (RARC) are used on the 835 ERA and paper EOB to provide supplemental information about a claim adjustment. They always accompany a CARC (denial code) and clarify the reason for payment differences.
A Denial Code (CARC) explains why payment was adjusted. A Remark Code (RARC) provides additional context or instructions. Both appear together on remittance — look for the CARC first, then the RARC for detail.
Search by code number or keyword, or filter by adjustment group (CO, PR, OA…). Click any code to see its full RA835 mapping, common causes, step-by-step resolution guide, and appeal tips.