CO – 4
The procedure code is inconsistent with the modifier used, or a required modifier is missing.
Check the Modifier and use the correct modifier or Add the Modifier. For example some lab codes requires QW modifier.
The procedure code/bill type is inconsistent with the place of service.
Check the POS and CPT combination. We can’t bill the procedure 99213 under the POS 21.
CO 20 & 21
This injury/illness is the liability of the no-fault carrier.
Check the DX. IF the patient has work related or Accident related injury then this claim should submitted to WC or No Fault insurance. Or change the DX and submit the claim.
The time limit for filing has expired.
Medicare has filing limit as maximum 2 year and Minimum one Year. If you have submitted the claim within the timely filing limit then appeal the claim with required proof. Or No other way just write off the claim.
Medicare denial reason code -1
Medicare denial reason code – 2
Medicare denial reason code – 3
Denial claim example
Medicare denial codes
For full list
Medicaid phone and address
Medical insurance billing