Key takeaways
- Medicare eliminated all remaining CMNs and DME Information Forms (DIFs) for dates of service on or after 1 January 2023.
- A claim submitted with a CMN or DIF attached is returned or rejected, so the form must not be sent.
- The supplier now keeps a standard written order, medical record support for the coverage criteria, and any item-specific attestation the policy asks for.
- The Statement of Certifying Physician for therapeutic shoes is the exception that still applies.
- Other payers, including Medicaid plans and commercial insurers, can have their own forms, so check each payer.
What a certificate of medical necessity was
A certificate of medical necessity (CMN) was a form on which the treating practitioner certified that an item of durable medical equipment was medically necessary. Suppliers kept it on file or sent it with the claim, depending on the item. A DME Information Form (DIF) was the supplier-completed counterpart used for some items. Oxygen was the best-known case, with CMS-484.
What changed on 1 January 2023
CMS announced in 2022 that it was eliminating all remaining CMNs and DIFs for claims with dates of service on or after 1 January 2023. This includes revised and recertified versions. The forms that went away:
| Form | Item it covered |
|---|---|
| CMS-484 | Oxygen |
| CMS-846 | Pneumatic compression devices |
| CMS-847 | Osteogenesis stimulators |
| CMS-848 | Transcutaneous electrical nerve stimulators (TENS) |
| CMS-849 | Seat lift mechanisms |
| CMS-854 | Section C continuation form |
| CMS-10125 (DIF) | External infusion pumps |
| CMS-10126 (DIF) | Enteral and parenteral nutrition |
What a DME supplier must have on file now
The medical necessity proof did not disappear. It moved from a form to the order and the medical record. Before billing, the supplier should hold:
- A standard written order (SWO) with the patient name or Medicare Beneficiary Identifier, a description of the item, the quantity when applicable, the order date, the ordering practitioner name or NPI, and the practitioner signature.
- A written order prior to delivery (WOPD) for items on the Required Face-to-Face Encounter and Written Order Prior to Delivery List. For other items, the order must reach the supplier before the claim is submitted.
- Diagnosis information from the treating practitioner.
- Medical record documentation showing the coverage criteria for the item are met.
- Any modifier or attestation information that the DME MAC policy for the item requires.
These records are not sent with the claim, but they must be available if Medicare asks for them.
What happens if a CMN is still attached
Medicare returns paper claims that carry a CMN or DIF, and electronic claims are rejected at the front end. The fix is to resubmit the claim without the form and to check the front-end edit reports when rejections appear. Billing systems and intake templates that still add a CMN step should be updated.
The exception: therapeutic shoes
The Statement of Certifying Physician for therapeutic shoes is still required. The DME MACs point suppliers to the form attached to the therapeutic shoes policy, so check the current policy before billing these items.
Quick checklist before you bill a DME claim
- Is the standard written order complete, signed and dated before the claim (or before delivery, if the item requires it)?
- Do the medical records support the coverage criteria for the item?
- Are the diagnosis and any required modifiers or attestations in place?
- Has the claim gone out without a CMN or DIF attached?
- For non-Medicare payers, did you check whether they still use their own form?
Related guides: how to bill DME claims, DME modifiers, CPAP E0601 billing and oxygen E1390 billing. For a second pair of eyes on your documentation process, see our DME billing services.
Certificate of medical necessity FAQs
Does Medicare still require a certificate of medical necessity for DME?
No. For dates of service on or after 1 January 2023, CMS eliminated the remaining CMNs and DIFs. Suppliers rely on the standard written order and the medical record instead. Therapeutic shoes still use the Statement of Certifying Physician.
Is CMS-484 still used for oxygen?
No. CMS-484, the oxygen CMN, is among the forms eliminated for dates of service from 1 January 2023. Oxygen claims depend on the written order and the medical record documentation the policy requires.
What replaced the CMN?
The standard written order, plus medical record documentation that supports the coverage criteria, diagnosis information, and any attestation or modifier information the item policy requires. Suppliers keep these on file and produce them if asked.
What happens if I send a CMN with the claim?
Medicare returns paper claims with a CMN or DIF attached, and electronic claims are rejected. Resubmit without the form.
Do other payers still require a certificate of medical necessity?
Some may. Medicaid programs and commercial insurers set their own documentation rules, so check each payer policy before assuming the Medicare change applies.
What is a CMN form in DME billing?
It was a form where the treating practitioner certified the medical need for an item such as oxygen. Medicare no longer uses these forms for dates of service from 1 January 2023, but the term still appears in older payer documents and training material.