It is important to enter correct codes for patient billing because the insurance needs to know what the patient is being diagnosed with so they can charge the right amount. When incorrect codes are entered by someone, the claim that was submitted can be rejected or denied. A rejected claims means that there is an error within the claim which means that the claim has to be corrected and resubmitted. A denied claim means the claim has been determined by an insurance company to be unpayable. Both types of claims are often denied or rejected because of common billing errors or missing information, but can also be denied based on patient coverage (Medical Billing