CO4 denial code description and corrective action

• A modifier is a two-digit (Numeric or alphanumeric) code added to a CPT or HCPCS procedure code in medical billing. It provides additional information about the service or procedure performed without changing its basic definition.

• For the use of modifiers, we must keep in mind their proper combination with the CPT code. If a modifier is not appropriate or does not align with the procedure code, the claim may be denied with this denial code.

• For example, if we bill a procedure code that relates to the right side of the body but use the modifier LT (which indicates the left side), the claim will be denied with this code as procedure code is inconsistent with the modifier used.

• Sometimes a modifier is necessary to provide complete and accurate information, but if we fail to include it, the claim will also be denied with this denial code as the required modifier is missing.

• For example, in physical therapy services, the GP modifier is often required. If this modifier is omitted, the claim will be denied with this denial code indicating that the modifier was required but missing.

Actions

• First, we need to verify the status of the claim. This can be done by checking the status through the insurance web portal or by calling the payer.

• The first and most important step is to determine whether the claim denial is valid or if the insurance has denied the claim by mistake.

• Call the insurance company if claims in the member’s history with the same coding have been paid, and ask the representative to reprocess the claim. Be sure to note the claim number and call reference number, and then follow up on the claim after the provided TAT.

• Consult coding specialists or use reliable websites to determine whether a modifier is required and if the modifier used is accurate or not.

• If the coding is correct, then we proceed with submitting an appeal.

• For submitting an appeal, we must calculate the timely filing limit starting from the processed date. If the limit has been exceeded, the claim will be denied again for exceeding the filing deadline. In such cases, we should consult with the provider. Some clients may still want us to submit the appeal even after the timely filing limit has passed, so we should proceed according to their instructions.

• If we determine that the denial is accurate, then we submit a corrected claim with the required modifications (Correct modifier).

• Sometimes we bill two service lines with the same procedure code using LT and RT modifiers. In such cases, the insurance may pay for one line and deny the other with this denial code. To resolve this, we submit a corrected claim with a single service line, double the charge amount, and append the bilateral modifier.

• Medicare does not accept corrected claims, so in the case of any denial, a new claim must always be submitted.

Description