Skip to Main Content
Web Content Viewer


Web Content Viewer

Chapter 7: Certificates of Medical Necessity/Durable Medical Equipment Information Forms 


A CMN or DIF are forms that help document the medical necessity and other coverage criteria for selected DMEPOS items. The Documentation section of each individual medical policy shows which items require one of these forms.

Certificates of Medical Necessity 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 a supplier-completed form and used by the DME MAC for claim processing purposes.  It does not require a physician signature or a narrative description of equipment and cost. You may complete and sign a DIF in its entirety.

For certain items or services billed to the DME MAC, the supplier must receive a signed CMN from the treating physician or the supplier must complete and sign a DIF. A supplier must have a faxed, photocopied, an original signed order, or an electronically signed version of a CMN or a completed DIF in their records before they can submit a claim for payment to Medicare. The CMS form number is located in the bottom-left corner of the form. CMNs and DIFs are referred to by their CMS form numbers. DME form numbers identify the CMN on electronic claims submitted to the DME MAC. For example, CMS Form 484 serves as the CMN for oxygen. CMS Form 10125 serves as the DIF for External Infusion Pump.

The DIF and a faxed, photocopied, an original signed order, or an electronic signed CMN must be maintained by the supplier and be available upon request. When hard-copy CMNs or DIFs are submitted to the DME MAC or ZPIC, the supplier must include a copy of only the front side. When a CMN is submitted electronically to the DME MAC, only information from Sections A, B and D is transmitted.

For additional requirements and instructions on how to properly complete CMNs and DIFs, please refer to Chapter 5 of the CMS IOM Publication 100-08, Medicare Program Integrity Manual, Sections 5.3, 5.3.1, 5.3.2, 5.3.3, 5.5, and 5.6.

Related Content

Web Content Viewer
Web Content Viewer
Complementary Content