Online instruction manual that the Centers for Medicare and Medicaid Services (CMS) transmits to Medicare carriers. It includes guidelines for processing and paying Medicare claims, preparing reimbursement forms, billing procedures, and Medicare regulations. The manual system has been replaced by online, Internet-only manuals (IOMs)—the, National Coverage Determinations Manual, Medicare Benefit Policy Manual, Publication 100 , one-time notifications, and manual revision and update notices. This information is helpful to providers when dealing with Medicare contractors for issues such as researching information, claims processing, and appealing denials. Formerly known as Medicare Coverage Manual (MCM) . See Medicare Coverage Manual (MCM) .