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Top Medical Denial Reason Codes Explained

November 30, 2020

When medical claims are denied, it costs practices money, resources and time. Not only has the practice wasted the time and effort it originally devoted to coding the claim, but it must now use additional resources to track down the reason for the denial and fix it. Only then can the claim once again be processed for payment. This also means the medical practice is without payment for a longer period of time. 

Below are the top medical denial codes. Also included are suggestions for ensuring that they don’t occur in the first place and/or for rectifying them for resubmittal. 

CO 4: Inconsistent modifier or required modifier is missing

A modifier is a two-character code that is either numeric or alpha-numeric. It’s used with CPT codes to indicate that a particular service was performed but altered in some specific way. In spite of that alteration, however, neither its code nor its definition changed. Avoid this claim denial by ensuring that the modifier used is both required and consistent with the code. 

CO 11: Diagnosis inconsistent with procedure

In order to apply the correct diagnosis code, the coder reviews the medical reports against the ICD 10 code. The diagnosis code that results is representative of the disease’s description. Ensure that payment has not already been submitted and received for the same diagnosis code and procedure on the same date of service (DOS). 

CO 16: Service and/or claim lacks necessary information

Often this denial code is accompanied by a remarks code if the claim is missing information or it includes information that is incorrect or invalid. The remarks code will highlight the exact information that is missing and necessary in order to correct the claim. 

Some examples of remarks codes include:

  • MA27: missing, invalid or incomplete name or entitlement number on claim
  • N245: invalid or incomplete plan information for other insurance
  • MA112: incomplete, invalid or missing group practice information
  • N286: missing, invalid or incomplete primary identifier for referring provider

CO 18: Duplicate Service or Claim

This denial code is self-explanatory. It occurs when a medical provider or the billing team submits the same service or claim more than once to the patient’s insurance company. Typically, the insurance company will process the original claim it receives while denying all subsequent claims. 

CO 22: Care might be covered by another payer due to coordination of benefits

Coordination of benefits (COB) rules determine which payer is the primary, secondary and so on for a particular patient who has more than one insurance. The patient is responsible for updating their insurance policy information so the right payer order is documented. Avoiding the CO 22 denial code can be accomplished by ensuring that the claim is submitted to the correct insurance in the right order. 

CO 29 Filing time limit has expired

Every insurance type and company sets timely filing deadlines for submitting claims. Unless the company receives the claim by that date, it will routinely be denied. If there is proof that the claim was submitted by the filing deadline, an appeal can be made to the appropriate insurance claims department. 

CO 50 Service not deemed medically necessary by the payer

When the procedure code and the diagnosis code are not compatible based on the local coverage determination (LCD) and national coverage determination (NCD) guidelines, the claim is denied. Some examples of why an insurance company might deny a claim with this denial code include — but are not limited to — the following: 

  • Physical therapy treatment that exceeds the limit set by the insurance company
  • Prescription drugs that are used for cosmetic services
  • Treatment administered by the hospital or provider that could have been delivered in a setting that was less expensive
  • Hospital service times that exceed that length approved by the hospital

The above is just a small sampling of the medical claims denial codes insurance companies use. As noted, many of these can be prevented simply by ensuring that the correct documentation is checked before the claim is submitted. Others can be attributed to simple human error. 

Coronis Health provides quick, accurate and timely medical billing and coding services for practices of all types and sizes. With more than 500 healthcare professionals on our team, Coronis Health offers compatibility with numerous EHRs and PM software as well as access to healthcare business intelligence. Contact us today and learn how this award-winning company can boost your revenue by 12 percent. 

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