The Full Form of CMN is Certificate of Medical Necessity.

A Certificate of Medical Necessity (CMN) or a DME Information Form (DIF) is a form required to help document the medical necessity and other coverage criteria for selected durable medical equipment, prosthetics, orthotics, and supplies (DMEPOS) items. CMNs contain sections A through D. Sections A and C are completed by the supplier and Sections B and D are completed by the physician. A DIF is completed and signed by the supplier. It does not require the cost, a narrative description of equipment or a physician’s signature.

For certain items or services billed to a DME MAC, the supplier must receive a signed CMN from the treating physician or a signed DIF from the supplier. A supplier must have a signed order and an electronic CMN or DIF in their records before they can submit a claim for payment to Medicare. CMNs or DIFs have a DME MAC form number (e.g. 01, 02, 03) and a revision number (e.g. .01, .02). Some forms also have an alpha suffix (e.g. A, B, C).

All CMNs and DIFs have a CMS form number in addition to the DME MAC form number. The CMS form number is in the bottom left corner of the form. CMNs and DIFs are referred to by their CMS form numbers. DME MAC form numbers identify the CMN on electronic claims submitted to the DME MAC..

A completed CMN or DIF must be maintained by the supplier and made available to the DME MAC on request. When hardcopy CMNs or DIFs are submitted to the DME MAC, the supplier must include a copy of only the front side. When CMNs are submitted electronically, information from sections A and B are required.

Noridian provides fillable CMNs and DIFs, in which data can be entered and printed. These interactive forms can be found on the Forms webpage.