CMS Pub. 100-04, ch. 27, § 20

NOTE: CMS seeks to reduce burden and modernize processes to ensure a reduction in

improper payments and an increase in customer satisfaction. The Certificate of Medical

Necessity (CMN) form and DME Information Form (DIF) were originally required to

help document the medical necessity and other coverage criteria for selected Durable

Medical Equipment, Prosthetics, Orthotics, and Supplies (DMEPOS) items. In the past, a

supplier received a signed CMN from the treating physician or created and signed a DIF

to submit with the claim. Due to improvements in claims processing and medical records

management, the information found on CMNs or DIFs is available either on the claim or

in the medical record and is redundant. Therefore, to reduce burden and increase

customer satisfaction, providers and suppliers no longer need to submit these forms for

services rendered after January 1, 2023.

• For claims with dates of service on or after January 1, 2023 – providers and

suppliers no longer need to submit CMNs or DIFs with claims. Due to electronic

filing requirements, claims received with these forms attached will be rejected and

returned to the provider or supplier.

• For claims with dates of service prior to January 1, 2023 – processes will not

change and if the CMN or DIF is required, it will still need to be submitted with

the claim, or be on file with a previous claim.

This statement applies throughout the Program Integrity Manual wherever CMNs and

DIFs are mentioned.

This section is intended only to be a brief profile synopsis of CWF operations. The

system and user documentation should be closely examined for further details.

The Common Working File system provides a single data source where the contractors

can verify beneficiary eligibility to receive prepayment review and approval of claims.

Each Host site is responsible for processing those claims submitted for beneficiaries on

its database. These claims are processed through a shared software system supplied to

each Host by the CWF Maintenance Contractor (CWFM). Each change made to the CWF

software is released to all Host sites in a uniform manner. This software performs

consistency and utilization editing on claims for corrective action by the MAC’s.

The CWF system ensures that:

1. The beneficiary is entitled to either Part A or Part B benefits, depending on

the type of claim submitted.

2. The co-pay and/or deductible applied, if any, is accurate.

3. Services are allowed.

4. Benefits are available for the services submitted on the claim

The CWF system also ensures that the services on the claim have not been paid on

another claim - either the same type or another type of claim. If any of these conditions

occur, the CWF system returns a response and identifies the reason for the rejection. The

response also includes one or more trailers that identify the correct information necessary

for the Medicare contractor to take the necessary action.

Prior to adjudication of claims, the CWF Host will send the claim to Fraud Prevention

System (FPS) for review. FPS will make a payment determination which will be sent to

the CWF Host. The CWF Host will then process the claims through consistency and

utilization to ensure beneficiary is entitled to either Part A or Part B benefits, depending

on the type of claim submitted.

Once the claim passes all of the edits, the CWF beneficiary master file is updated to

reflect the benefits now available, as well as any changes to the deductible status. The

claim is added to the CWF full claim history file.

CWF also provides eligibility and entitlement check via the beneficiary data streamlining

(BDS) system which occurs earlier in the claims lifecycle to check for Medicare

beneficiary identifier, eligibility and entitlement prior to the submission of the claim.