Medical Billing Denial Codes

The modifier doesn't match the procedure code. Common with Mod 25, Mod 59/X modifiers, and component billing (Mod 26/TC).

Claim lacks required data for adjudication. Usually a missing modifier, NPI, or diagnosis pointer.

Payer says another insurance should pay first. Birthday Rule, Medicare MSP rules, primary vs secondary determination, and how to prevent the COB-to-timely-filing death spiral.

Payer flagged this as a duplicate of a previously submitted claim or service.

Claim submitted after the payer's deadline. May be permanently lost, but 5 specific exceptions can save it. Includes deadlines by payer.

The CPT/HCPCS code is not valid for the date of service or doesn't match the diagnosis.

Service required prior auth and none was on file. Retro-auth policies by payer, appeal strategies, and the verification system that prevents it.

Claim was paid but at a reduced amount. NCCI bundling, multiple procedure reductions, and fee schedule errors. How to audit and recover the difference.

Billed amount exceeds the contracted rate. Technical fees or negotiated adjustments applied.

The patient's health identification number doesn't match the name on file with the payer.

Payer deems the service wasn't needed. The most appealed denial code in billing. Appeal framework with LCD/NCD citations and peer-to-peer review guide.

The provider is not credentialed, enrolled, or authorized to bill for this service.

The National Provider Identifier on the claim doesn't match the payer's records.

The National Provider Identifier is missing, incomplete, or in an invalid format.

The NPI was submitted in an incorrect format. Check digit calculation or length error.

Service is not covered under the patient's current benefit plan. Patient is responsible for payment.