Denials in medical billing
A denial occurs when an insurance company refuses to pay or process a claim for any reason. Understanding each denial and its cause is the first step to the right corrective action.
61 denial codes
Denial categories
In medical billing, handling denials is an essential part of the process. Here we cover the common and frequently occurring denials, with the reason and the proper corrective action for each. Most denials arrive under two categories, CO and PR. Occasionally you may also see OA.
CO: Contractual Obligation
The adjusted (denied) amount is based on the contract between the provider and the insurance.
It is never the patient’s responsibility. Any amount with a CO category code cannot be billed to the patient.
PR: Patient Responsibility
The patient owes this amount. Neither the insurance, the provider nor any other party is responsible for it.
When billing the patient, only copay, coinsurance, deductible or paid-to-patient amounts should be billed.
OA: Other Adjustments
Adjustment codes that do not fit into any other category, such as CO or PR.
Select any denial below to see its reason, description and the proper corrective action.
Patient responsibility (PR)
Contractual (CO)
- 4Inconsistent / Missing modifier.
- 5Procedure code is inconsistent with place of service.
- 6Procedure/Revenue code is inconsistent with patient’s age.
- 7Procedure code is inconsistent with patient gender.
- 8Procedure is inconsistent with provider taxonomy.
- 9Diagnosis is inconsistent with patient’s age.
- 10Diagnosis is inconsistent with patient’s gender.
- 11Diagnosis is inconsistent with procedure.
- 12Diagnosis is inconsistent with the provider taxonomy.
- 13Date of death precedes DOS.
- 14DOS precedes DOB (date of birth).
- 16Lack of information in claim.
- 18Exact duplicate service/claim.
- 19Liability of workers’ compensation as it is a work-related injury/illness.
- 20This injury/illness is covered by liability carrier.
- 21This illness/injury is liability of no-fault carrier.
- 22Covered by another payer per COB (coordination of benefits).
- 23Impact of prior payer.
- 24Charges covered under capitation agreement.
- 26Expenses incurred prior to the coverage start.
- 27Expenses incurred after coverage terminated.
- 29Timely filing limit (TFL) expired.
- 31Patient cannot be identified as our insured.
- 45Charges exceed maximum allowable fee schedule.
- 49Noncovered as it is routine/preventive exam or screening procedure done in conjunction with routine/preventive exam.
- 50Services not deemed medically necessary by the payer.
- 51Services are noncovered as this is a pre-existing condition.
- 55Services/Drug deemed experimental or investigational by the payer.
- 96Noncovered services (Unspecified).
- 97Payment for this service is bundled/inclusive with another service already adjudicated.
- 109Services not covered by this payer, you must send them to correct payer/insurance.
- 119Maximum benefits have been reached.
- 129Prior processing information appears incorrect.
- 140Patient/Subscriber’s identification number or name mismatched.
- 146Invalid diagnosis for the DOS.
- 150Information submitted doesn’t support this level of service.
- 151Information submitted doesn’t support this many/frequency of service.
- 163Attachment or other documentation referenced on the claim was not received.
- 181Procedure code was invalid on DOS.
- 182Modifier was invalid on DOS.
- 183Referring provider is not eligible to refer for the service billed.
- 185Rendering provider is not eligible to perform the service billed.
- 197Precertification/authorization absent.
- 199Revenue code and procedure code mismatched.
- 226Information requested from billing/rendering provider was either received after allowed time, incomplete, or not yet received.
- 227Information requested from patient/subscriber was not provided or was insufficient/incomplete.
- 234This procedure is not paid separately.
- 236This procedure or procedure/modifier combination is not compatible with other procedure or procedure/modifier combination.
- 242Services not provided by network/primary care physician.
- 252Missing documentation.
- 288Referral absent.
Other codes
- B7Provider is not eligible to be paid for this service on this DOS.
- B9Patient enrolled in Hospice.
- B16New patient qualifications were not met.
- B20Procedure or service was fully or partially performed by another provider.
- M119Missing/Incomplete/Invalid National Drug Code (NDC).
- MA120Missing/Incomplete/Invalid CLIA certification number.
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