The Centers for Medicare & Medicaid Services (CMS) employs several types of Review Contractors (RCs) to measure, prevent, identify, and correct improper payments under the Medicare Fee-for-Service (FFS) program. RCs find improper payments by selecting a small sample of claims, requesting medical documentation from the provider who submitted the claims and manually reviewing the claims against the medical documentation to verify the providers' compliance with Medicare rules. In the past, medical documentation providers had only two options for delivering the requested medical documentation – via mail or fax. In September 2011, CMS implemented a new system or secure exchange gateway called the Electronic Submission of Medical Documentation (esMD) for providers to send/receive documentation to/from RCs through their represented agents called Health Information Handlers (HIHs). The esMD system gives providers the option of sending medical documentation electronically.