Medical claim denial codes, explained

Look up a CARC or RARC denial code to see what it means, why it happens, and how to fix it.

CO-45

The amount billed is higher than the payer's contracted (allowed) rate. The difference is a contractual write-off, not a patient balance.

CO-16

The claim is missing required information or has an error. It is almost always paired with a RARC that names the specific missing field.

CO-97

This service is bundled into another service that was already paid, so it is not paid separately.

CO-18

The payer received this exact claim/service already.

CO-22

Another insurer should be billed first under coordination of benefits.

CO-29

The claim was submitted after the payer's filing deadline.

CO-50

The payer decided the service was not medically necessary as billed.

CO-96

The service is not covered under the plan. Often paired with a RARC explaining why.

CO-97-N290

The rendering provider's NPI is missing, incomplete, or invalid on the claim.

CO-109

This is the wrong payer for the claim.

CO-197

A required prior authorization, precertification, or notification was not obtained.

CO-204

The item or service is not a covered benefit under this plan.

PR-1

This amount is applied to the patient's deductible and is the patient's responsibility.

PR-2

This amount is the patient's coinsurance and is their responsibility.

PR-3

This amount is the patient's copay and is their responsibility.

CO-11

The diagnosis code does not match or support the procedure billed.

CO-4

A modifier is missing or wrong for the procedure billed.

CO-27

The patient's coverage had ended before the date of service.

CO-31

The payer cannot match the patient to a member record.

CO-B7

The provider was not credentialed or enrolled with the payer for that date/service.

CO-151

The billed frequency or quantity exceeds what the payer allows or the documentation supports.

CO-119

The patient has hit a benefit maximum (visits, dollars, or occurrences) for the period.

CO-24

The service is covered under a capitation or managed-care arrangement, not fee-for-service.

CO-234

The procedure is not separately payable; its value is included in another service.

CO-146

The diagnosis code was not valid for that date of service.

CO-140

The member ID and patient name on the claim do not match the payer's records.

CO-170

This provider type is not allowed to bill this service to the payer.

CO-252

The payer needs supporting documentation before it can process the claim.

PR-49

A routine or preventive service is not covered (or was billed with a routine exam), and it is patient responsibility.

CO-6

The procedure billed does not fit the patient's age per payer edits.

CO-183

The referring provider on the claim is not eligible to make the referral.

MA130

The claim is unprocessable due to incomplete/invalid information, so it was not adjudicated (and has no appeal rights until corrected).

N130

The service is subject to plan restrictions; check the benefit documents.

M76

The diagnosis is missing, incomplete, or invalid on the claim.