Every week: one denial code decoded. What it means, why payers use it, what you do about it, and the appeal script to use. No jargon. No hedging.
CO-197 is the prior authorization absent denial. It means your payer expected an auth number on the claim and it was not there. Here is the exact path to recovery, including the retro-auth window most billers miss.
Read the guide →Timely filing denials feel final. Many are not. Here is how to write the appeal.
Read →M127 is a documentation denial. This is what you need to send to get paid.
Read →Frequency denials are among the most appealable in Medicare. Here is how.
Read →One code per post. Meaning, cause, action steps, appeal script. Bookmark the one costing you the most money first.
Retro-auth window, appeal steps, and exactly what documentation to send to get the claim paid in full.
Full guide →Timely filing is not always final. Learn when you can appeal and what proof of timely filing actually looks like.
Full guide →Modifier mismatches are fast to fix once you know which modifier the payer expects for that procedure.
Full guide →Progress notes and treatment plan. That is usually all it takes to overturn a CO-151. Here is the appeal template.
Full guide →PR denials are patient responsibility. But the amount shown is not always what you can collect. Here is the compliance line.
Full guide →M127 is one of the most specific RARCs. It tells you exactly what document the payer is missing. Here is how to respond.
Full guide →OA-23 shows up most often in Medicare secondary billing. It is not a denial of coverage, it is a coordination-of-benefits adjustment.
Full guide →Duplicate denials are often wrong. The claim is not a duplicate, it is a resubmission. Here is how to document the difference.
Full guide →Medical necessity denials require clinical documentation. Here is the appeal structure and what reviewers look for.
Full guide →Every denial code starts with a group indicator. This is the most important two letters on your ERA, and most billers never learn to read it quickly.
The payer considers this a provider responsibility. You agreed to write this off as part of your contract. You cannot bill the patient for CO adjustments under most contracts.
The patient owes this. Deductibles, copays, coinsurance. You can bill the patient — but verify the patient is not also covered by a secondary plan before collecting.
Neither the provider nor the patient is directly responsible. Coordination of benefits, Medicare secondary processing, and similar adjustments land here.
The payer reduced the payment on their own initiative. You may be able to appeal if the reduction conflicts with your contract rate.