The First Part of Medical Billing: Medical Coding Many people think medical coding and medical billing are the same thing, as you in the industry know, they are part of the same process but are very different. Medical coding is where it begins, the services are rendered and the standardized insurance codes that correspond to that service are recorded on a medical billing form. The codes can be changed/added to/or removed many times in one year and if an outdated code is used, it can cause your medical billing claim to be rejected. If incorrect coding or under/over coding is used, you can be setting yourself up for an audit. …