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common denial codes

Denials of a healthcare insurance claim is one of the most irritating things a healthcare provider or a medical biller can experience. Common denial codes help with re-filing reimbursement claims – however, it takes time and effort. Therefore, getting your claims right the first time is highly important; it is always better to outsource to a medical billing services provider. Third-party billers are experts in handling billing and preventing denials, so you are safe.

While we talk about the common reasons for denied claims, these include:

  1. Billing Errors
  2. Missing Information
  3. Questions regarding patient coverage

2024 Common Denial Codes in Medical Billing

Let’s take a look in detail at the common denial codes in 2024:


The denial code CO-15 corresponds to a claim that has a wrong authorization number for a procedure or a service.

You shall need prior approvals for proper coverage, especially for specific treatments or procedures. After getting this approval, you must enter the correct prior authorization number in block 23. This particular block is on the CMS-1500 form.

  • Furthermore, getting this denial code explicitly means there is a problem. This denial code can be addressed firstly by:
  • Reviewing claims to see whether you or your team submitted the prior authorization request.
  • By rechecking block number 23 to locate any errors.

It is one of the common denial codes, and if the pre-authorization is not available, try and get retro authorization for the particular claim.


Additionally, CO-16 is another one of the common denial codes that a person comes across in healthcare billing. You might get CO-16 if you submit a claim with missing information or incorrect/misplaced modifiers. Some reasons for CO-16 denial include the following:

  • Technical Errors
  • Demographic Errors
  • Missing Social Security number entry
  • CLIA number (Invalid Clinical Laboratory Improvement Amendments (CLIA) number)

For navigating the CO-16 claims denial, as a provider/biller, you must heed any of the accompanying remark codes. Furthermore, these codes are specifically there to help you further define what information is missing from your claim so you can make changes accordingly.


The denial code CO-29 is another one of the common denial codes. It means that you sent a claim after the deadline for submission. Every health plan has a specific submission timeframe, so you must know your payor requirements.

In case you receive a denial code CO-29, you must:

  • Recheck the date you submitted the initial claim
  • Calculate the date of submission and find out whether you put submission before the deadline

Also, take proof of a timely filing for filing an appeal


The CO 222 denial code denotes instances where maximum contracted hours/days or units are exceeded by a provider for a particular period.


Lastly, let’s discuss the denial code CO-45, which marks a fee that exceeds the highest allowed amount for a service charge. The particular denial code can also be a part of group code patient responsibility (PR), depending on the liability. Additionally, the PR-45 is triggered when a patient is responsible for the adjustment. To make it more transparent, it involves copays and deductibles.


Healthcare insurance plans do not cover every procedure that a patient might need. For such cases, payers mostly use the denial code CO-167 to reject claims that do not fall under their coverage.

For handling the common denial codes, especially the CO-167, you must:

  • Evaluate (ICD-11) the diagnosis codes in the event of errors
  • Get in touch with the payer to assess what diagnoses are not covered
  • Facilitate necessary adjustments, then resubmit the correct claims.

Final Word

Correction of coding errors accounts for as much as 81% of claim denials. The best part is that the common medical billing denials are avoidable. With thorough vetting of data, collecting proper patient data, and even relying on the best software – your medical practice can efficiently practice that are experts in claims handling. At Physicians Revenue Group, Inc., we are experts at common denial codes and offer a range of claims-related services that can assist your practice in avoiding healthcare billing denials.

Frequently Asked Questions

Co 97 denial code occurs because the benefit for a service in the allowance/payment for another service that was already adjudicated.

These types include:

  1. Hard denials
  2. Soft denials

The hard denials are irreversible, and more often than not result in written-off or lost revenue. Furthermore, the soft denials are temporary which can be potentially reversible if providers offer additional information, or correct the claims.

The claim denials are the refusal of an insurance provider to honor a request for paying for healthcare services obtained from a healthcare provider.