Social Security Act Sections 1833(e) and 1834(j)(2); 42 U.S.C. Section 1395m(j)(2)(1998); 42 C.F.R. Section 410.38; CMS Manual System, Pub. 100-04, Medicare Claims Processing Manual, Chapter 20, Section 100.2; CMS Manual System, Pub. 100-08, Medicare Program Integrity Manual, Chapter 5; CMS Ruling 93-1, CMS Change Request 4296 and 5571

• Certificate of Medical Necessity (CMN) and DME Information Forms (DIF) Elimination
• Acceptable CMNs
• Acceptable DIFs
• Instructions for Completing a CMN and DIF
• DIF Specific Instructions
• CMN Cover Letters
• Transmission of CMN
• Changes to Completed CMN
• Physicians Charging for CMN Completion
• CMNs as Orders and Claim Submission
• Evidence of Medical Necessity for Oxygen CMN
• Initial Certification
• Treating Physician Identification
• Revised Certification CMNs
• Oxygen CMNs - Scheduling and Documenting Recertification CMNs
• Replacing Oxygen Equipment - CMN Requirements
• Initial CMN (for replacement equipment)
• Recertification CMN (for replacement equipment)

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.

Acceptable CMNs

The following table identifies the CMNs that are accepted for claims for items requiring a CMN.

Acceptable DIFs

The following table identifies the DIFs that are accepted for claims for items requiring a DIF.

Instructions for Completing a CMN and DIF

Social Security Act Section 1834(j)(2); 42 U.S.C. Section 1395m(j)(2); CMS Manual System, Pub. 100-08, Medicare Program Integrity Manual, Chapter 5

The Initial Date found in Section A of the CMN should be either the specific date that the physician gives as the start of the medical necessity or if no specific start date is given, the Initial Date would be the date of the order.

The Signature Date is the date the physician signed and dated Section D of the CMN. This date might not be the same as the Initial Date, since the Signature Date must indicate when the physician signed Section D of the CMN.

Signature and date stamps are not acceptable for use on CMNs and DIFs. Hand written, facsimiles of original written and electronic signatures and dates will only be accepted by the DME MACs.

The Date of Service on the claim must not precede the Initial Date on the CMN or DIF or the start date on the written order. To ensure that an item is still medically necessary, the date of service must be within three months from the Initial Date of the CMN or DIF or three months from the date of the physician's signature.

For revised CMNs or DIFs, physicians (for CMNs) or suppliers (for DIFs) must enter the total cumulative number of months from the initial date in which the item will be needed when entering the estimated length of need. For instance, if an initial CMN/DIF has an original length of need of five months and the physician wishes to extend the length of need (LON) for an additional three months, then the LON on the revised CMN or DIF must be entered as eight months (the total number of months from the initial date).

The DME MACs, Unified Program Integrity Contractors (UPICs) have the authority to request to verify the information on a CMN or DIF at any time. If the information contained either in the supplier's records or in the beneficiary's medical record maintained by the ordering physician fails to substantiate the CMN or DIF, or if it appears that the CMN or DIF has been altered, the DME MACs and UPICs should deny the service and initiate the appropriate administrative or corrective actions.

In the event of a post pay audit, the supplier must be able to produce the CMN or DIF and if requested by the DME MACs and UPICs produce information to substantiate the information on the CMN or DIF. If the supplier cannot produce this information, the DME MACs and UPICs will deny the service and initiate the appropriate administrative or corrective actions.

DIF Specific Instructions

Initial DIF

The first DIF filed for a particular beneficiary and item is the initial DIF.

A new initial DIF is also required when:

1. An enteral formula is billed with a different HCPCS code, which has not been previously certified, is ordered; or
2. For either enteral formulas or administration via pump (B9002), there has been a break in billing of more than 60 days (plus the remaining days in the rental month) and there has also been a change in the underlying medical condition that justifies coverage for the item(s) (i.e., break in need/medical necessity); or
3. A beneficiary receiving enteral nutrition by the syringe or gravity method is changed to administration using a pump*(B9002).

*Change in method of administration from gravity or syringe to pump (B9002) requires a new initial DIF for the pump and a revised DIF for the enteral nutrient.)

Revised DIF

When changes are made to an initial DIF, a revised DIF must be completed. A revised DIF is required when:

1. For nutrition;
   1. There is a change in HCPCS code for the current enteral nutrient billed; or
   2. The number of days per week administered is changed; or
   3. The physician provides a new order changing the amount of calories administered; or
   4. Change in the method of administration from gravity to syringe or syringe to gravity (see above for gravity or syringe to pump); or
   5. Change in route of administration from tube feeding to oral feeding (if billing for denial); or
   6. Length of need on a previous DIF has expired and physician is extending the LON.
2. For infusion pumps;
   1. There is a change in the drug HCPCS code; or
   2. The route of administration changes; or
   3. The method of administration changes; or
   4. Length of need on previous DIF has expired and physician is extending the LON

Note: You should submit a revised DIF with the first claim affected by the change(s).

CMN Cover Letters

CMS Manual System, Pub. 100-08, Medicare Program Integrity Manual, Chapter 5, Section 5.3.2

The Social Security Act to specifies the types of information that suppliers may provide to physicians in a CMN. These are limited to an identification of the supplier and beneficiary, a description of the equipment and supplies being ordered, procedure codes for the equipment and supplies, and other administrative information not related to the medical condition of the beneficiary.

Cover letters can be used by a supplier as a method of communication between the supplier and the physician. It is not CMS' intent to restrict necessary communication between the supplier and the physician. CMS does not require nor regulate the cover letter.

Information contained in cover letters should address issues related to CMS or DME MAC regulation/policy changes, brief descriptions of the item(s) being provided, and changes in the beneficiary's regimen. Suppliers are encouraged to include language in their cover letters to remind physicians of their responsibility to determine both the medical need for, and the utilization of, all healthcare services, and to ensure that information relating to the beneficiary's condition is correct.

Section C of the CMN was designed not only to provide the physician with charge information, but also to function as a confirmation of the physician's order. However, if suppliers wish to duplicate physician order information in a cover letter, they should feel free to do so.

Transmission of CMN

Social Security Act Section 1833(e); CMS Manual System, Pub. 100-08, Medicare Program Integrity Manual, Chapter 5, Section 5.3

Printable copies of the CMN and DIF forms are available on the CMS website.

The CMN sent to the physician must be two-sided with instructions on the back. If the CMN is mailed to the physician, the supplier must send the two-sided form. If the CMN is faxed, the supplier must fax both the front and back of the form. It is in the supplier's interest to maintain a copy of what they faxed to the physician.

Suppliers must maintain a copy of the completed CMN or DIF in their records. However, if the physician only faxes the front of the completed CMN then the supplier is only required to maintain the front portion of the CMN. The DIF must also be two-sided with instructions on the back and completed by the supplier. Because these forms have been approved by the Office of Management and Budget (OMB), when a CMN or DIF is submitted with a paper claim, the hardcopy must be an exact reproduction of the CMS form.

Without exception, these modified hardcopy forms must contain identical questions/wording to the CMS forms, in the same sequence, with the same pagination, and identical instructions/definitions printed on the back. CMN question sets may not be combined.

Suppliers and physicians may choose to utilize electronic CMNs (e-CMNs) or electronic DIFs (e-DIFs). E-CMNs or e-DIFS must adhere to all privacy, security, and electronic signature rules and regulations published by CMS and the Department of Health and Human Services (DHHS). Additionally, e-CMNs or e-DIFs must contain identical questions/wording to the CMS forms, in the same sequence, with the same pagination, and identical instructions/definitions as printed on the back of the hardcopy form.

When a UPIC is investigating potentially fraudulent behavior by a supplier, it will be the supplier's responsibility to prove the authenticity/validity of the claim(s) under investigation. A UPIC may require the supplier to prove the authenticity/validity of the signature on the CMN, DIF, order or any other questionable portion of the claim(s) under investigation.

Changes to Completed CMN

CMS Manual System, Pub. 100-08, Medicare Program Integrity Manual, Chapter 5, Section 5.3.1

If there is a change made to any section of the CMN after the physician has signed the CMN, the physician must either line through the error, initial, and date the correction or the supplier may choose to have the physician complete a new CMN.

Physicians Charging for CMN Completion

Charging suppliers a fee for completing Medicare required CMNs may be considered a potential felony by the Office of Inspector General (OIG). When physicians bill for their services, including examination, diagnosis, and treatment, any costs associated with paperwork are considered part of the charges made for their professional services. If a physician's patient genuinely needs an item of durable medical equipment, the completion of a CMN is a service to the physician's patient rather than the supplier.

CMNs as Orders and Claim Submission

42 C.F.R. Section 410.38; CMS Manual System, Pub. 100-08, Medicare Program Integrity Manual, Chapter 5

The CMN can serve as the physician's detailed written order if the narrative description in section C is sufficiently detailed. This would include quantities needed and frequency of replacement for accessories and supplies. For items requiring both a CMN and a written order prior to delivery (e.g., seat lift mechanisms) suppliers may utilize a completed and physician-signed CMN for this purpose. Otherwise, a separate order in addition to a subsequently completed and signed CMN is necessary.

The supplier may not complete the information in section B of the CMN. A supplier who knowingly and willfully completes section B of the form is subject to a civil monetary penalty up to $1,000 for each form or document so distributed. Any supplier who remains in non-compliance after repeated attempts by the contractor to get the supplier into compliance, refer to your RO (for UPICs refer the supplier to the primary GTL or associate GTL and SME) as a potential civil monetary penalty case.

The fee schedule amount, narrative description of the items furnished and the supplier's charge for the medical equipment or supplies being furnished must be completed on a CMN by the supplier prior to it being furnished to the physician. A supplier who knowingly and willfully fails to include this information may be subject to a civil monetary penalty up to $1,000 for each form or document so distributed. Any supplier who remains in non-compliance, after repeated attempts by the contractor to get the supplier into compliance, refer to your RO (for UPICs, refer the supplier to the primary GTL or associate GTL and SME) as a potential civil monetary penalty case.

CMS will not accept any other certifications of medical necessity by other insurers or government agencies.

Suppliers and physician may choose to utilize electronic CMNs (e-CMNs) or electronic DIFs (e-DIFs). E-CMNs or e-DIFS must adhere to all privacy, security, and electronic signature rules and regulations promulgated by CMS and DHHS. Additionally, e-CMNs or e-DIFs must contain identical questions/wording to the CMS forms, in the same sequence, with the same pagination, and identical instructions/definitions as printed on the back of the hardcopy form.

If an item requires a CMN or a DIF and the supplier does not have a faxed, photocopied, original hardcopy, or an electronic signed CMN or DIF in their records when they submit a claim to Medicare, the claim will be denied.

In cases where two or more suppliers merge, the resultant supplier should make all reasonable attempts to secure copies of all active CMNs or DIFs from the supplier(s) purchased. This document should be kept on file by the resultant supplier for future presentation to the DME MACs, and UPICs.

Evidence of Medical Necessity for Oxygen CMN

CMS Manual System, Pub. 100-03, Medicare National Coverage Determinations Manual, Chapter 1, Section 240.2, CMS Manual System, Pub. 100-04, Medicare Claims Processing Manual, Chapter 20, Section 100.2.3; CMS Manual System, Pub. 100-08, Medicare Program Integrity Manual, Chapter 5, Section 5.9.1

If DME MACs or UPICs learn that the physician on record is no longer the treating physician, the supplier shall obtain from the physician currently responsible for the beneficiary's pulmonary condition a current, fully-completed oxygen CMN. After review of this oxygen CMN, DME MACs continue monthly payments if the evidence establishes medical necessity. Their records must be updated to identify the new treating physician.

For more information concerning coverage and claim submission for oxygen therapy, see the medical policy for Oxygen and Oxygen Equipment.

Initial Certification

CMS Manual System, Pub. 100-03, Medicare National Coverage Determinations Manual, Chapter 1, Section 240.2; CMS Manual System, Pub. 100-04, Medicare Claims Processing Manual, Chapter 20, Section 100.2.3

For the situations that require an initial oxygen CMN, refer to the local coverage determination (LCD) for Oxygen and Oxygen Equipment. In determining coverage, the dates of treatment and testing are critical. For example, the initial date of need for home oxygen coverage cannot precede the date of the order or the date of the test(s), the results of which are used to determine if the coverage criteria are met. Once coverage is established, the estimated LON, along with the circumstances and results of testing that established the medical necessity at the start of home oxygen therapy, will determine when recertification is necessary.

Qualifying tests must be conducted by the treating physician or a provider certified to conduct such tests. Because of the potential for conflict of interest, the results of oximetry tests conducted by a DME supplier cannot be accepted to establish the need for home oxygen therapy services, either in initial claims or when accompanying recertification CMNs. This prohibition does not extend to the results of tests conducted by a hospital that is a certified provider of such services that may also be furnishing home oxygen therapy to the beneficiary.

The date of oxygen testing must be within 30 days prior to the date of initial certification. Therefore, for initial oxygen certification, the CMN may be completed by the physician no more than 30 days prior to initial coverage of oxygen. An exception to this is if a beneficiary begins taking oxygen while under a Medicare Advantage Plan. In this situation, the supplier must obtain an initial CMN and submit it to the DME MAC at the time that fee for service (FFS) coverage begins; however, the beneficiary does not have to obtain the blood gas study on the CMN within 30 days prior to the date on the CMN. In this situation, the test must be the most recent study the beneficiary obtained while in the Medicare Advantage Plan, under the guidelines specified in the medical policy. It is important to note that just because a beneficiary qualified for oxygen under a Medicare Advantage Plan, it does not necessarily mean that beneficiary will qualify for oxygen under FFS. These instructions apply whether a beneficiary voluntarily returns to FFS or if the beneficiary involuntarily returns to FFS because their Medicare Advantage Plan no longer participates in the Medicare + Choice program.

When both arterial blood gas (ABG) and oxygen saturation (oximetry) tests have recently been performed, greater weight is given to the ABG result. That test is generally acknowledged as the more reliable indicator of hypoxemia. In a review situation, if documentation in the medical record contains the result of an ABG performed on the same day as an oximetry saturation recorded on the CMN, and they are the most recent tests taken on or before the certification date on the CMN, the ABG will be used to determine oxygen coverage for that certification. If the ABG does not substantiate the need for oxygen therapy, the claim(s) will be denied as not reasonable and necessary.

There are no professionally accepted formulas for converting the results of tests taken while the beneficiary is on oxygen to what the same beneficiary would have shown had he or she been breathing room air. Coverage may not be established by use of any suggested formula to convert this information.

Where PO2 levels exceed 59 mm Hg or the arterial blood oxygen saturation exceeds 89 percent at rest, a rebuttable presumption of noncoverage exists. Form CMS-484 certification must be supplemented by additional documentation from the attending physician designed to overcome this presumption and justify the oxygen order, including a summary of other, more conservative therapy that has not relieved the beneficiary's condition.

CMS stipulates that claims may be denied without development if:

• The only qualifying test results came from oximetry tests conducted by a supplier of DME other than a hospital;
• The claim lacks information necessary to justify coverage in accordance with guidelines in section 240.2 of the Medicare National Coverage Determinations Manual;
• Hardcopy claims where Form CMS-484 lacks the treating physician's signature; or
• Electronic claims where Form CMS-484 fails to indicate the attending physician's handwritten signature is on file in the supplier's office.

Treating Physician Identification

CMS Manual System, Pub. 100-04, Medicare Claims Processing Manual, Chapter 20, Section 100.2.3.3

Form CMS-484 must be personally signed and dated by the treating physician, nurse practitioner, physician assistant or clinical nurse specialist.

Revised Certification CMNs

CMS Manual System, Pub. 100-04, Medicare Claims Processing Manual, Chapter 20, Section 100.2.3

New medical documentation written by the beneficiary's treating physician must be submitted to the DME MAC in support of revised oxygen requirements when there has been a change in the beneficiary's condition and need for oxygen therapy; therefore, physicians are encouraged to file a revised Form CMS-484 as soon as possible when the order for oxygen changes. A revised certification is appropriate under the circumstances described in the Oxygen and Oxygen Equipment LCD.

Oxygen CMNs - Scheduling and Documenting Recertification CMNs

CMS Manual System, Pub. 100-04, Medicare Claims Processing Manual, Chapter 20, Section 100.2.3.1

Recertification scheduling and documentation requirements depend on the date when home oxygen therapy began. See the policy Oxygen and Oxygen Equipment for situations requiring a recertification. The following information is needed on all recertified CMNs:

• Date and results of the most recent arterial blood gas or oximetry tests conducted prior to the recertification date;
• Name of the provider conducting the most recent ABG or oximetry tests prior to the recertification date;
• The conditions under which these tests were conducted;
• Estimated length of need for oxygen (in section B of Form CMS-484);
• Date of the current oxygen order; and
• Details of the current oxygen order.

Additionally, for beneficiaries who initially qualify for oxygen coverage with Group II blood gases, a repeat blood gas study must be performed between the 61st and 90th day of home oxygen therapy. For those whose physician's estimated length of need is less than lifetime, repeat blood gas determinations must be performed within 30 days prior to recertification.

The schedule for recertifying the need of oxygen for beneficiaries beginning home oxygen therapy is established in accordance with the requirements below.

First Recertification Required at Three Months: The Omnibus Budget Reconciliation Act (OBRA) of 1990 requires earlier recertification and retesting of oxygen beneficiaries based on test results that do not meet the presumed coverage levels, i.e., an ABG result of 55 or less or an arterial oxygen saturation of 88 percent or less. Payment may be made for the fourth month of service only upon presentation of test results that meet presumed coverage levels. The recertification at three months must reflect the results of an arterial blood gas or oxygen saturation test conducted between the 61st and 90th day of home oxygen therapy. If the beneficiary no longer requires home oxygen therapy after three months, retesting is not necessary.

Recertification CMNs at three months should be completed in full. If the order has already been discontinued, the physician should write the date that it was stopped.

The request for recertification to the physician will be made through the supplier of oxygen. The physician should be instructed to complete the recertification CMN and return it to the supplier. The supplier must then forward a copy of this information with a hardcopy claim or transcribe it exactly as it appears into the record of an electronic claim for the fourth monthly payment for oxygen therapy. The physician should be encouraged to retain a copy of this recertification CMN. The supplier or physician must retain a copy of the completed CMN form CMS-484. No payment will be made for the fourth or later months of oxygen service unless the recertification CMN and retest results establish continuing medical necessity.

Recertification for Long Term Therapy: Other than those beneficiaries for whom early recertification is required, recertification is required after the beneficiary has been receiving oxygen therapy for nine months. This will allow up to 90 days for the physician to submit a recertification CMN.

If additional tests have been conducted since the prior certification, these results and other pertinent information must be recorded on the recertification. Additional testing will not be requested for beneficiaries with established chronic pulmonary problems.

The supplier must send recertification requests to the attending physician for completion. The supplier should emphasize that the completed Form CMS-484 is to be returned to the supplier in all cases. To reduce misrouting problems, the supplier may want to provide self-addressed, return envelopes. The supplier must forward a copy of the completed Form CMS-484 with its next claim for monthly rental of oxygen equipment. It is advisable for the physician to retain a copy of the completed Form CMS-484 with other records for the beneficiary. The supplier must retain a copy of the completed CMN Form CMS-484.

While the recertification is being obtained, payments will continue through the 12th month of service, based on the estimated length of need for oxygen therapy in the initial certification. Payment will be suspended for the 13th or later months if a satisfactory recertification CMN, including any test results that may be required, has not been received by the time the payment would otherwise be authorized.

Subsequent Recertification CMNs: Most all beneficiaries who require home oxygen therapy beyond a few months require it lifelong. Therefore, once a Form CMS-484 recertification establishes that the medical necessity continues, subsequent recertification CMNs are not routinely required. However, they may be requested in conjunction with quality control sampling or if there is an indication of significant change in the beneficiary's status, e.g., large, unexplained variations in the use of oxygen or evidence of confinement to a hospital or skilled nursing facility (SNF) throughout an equipment rental period. Because orders have a fixed, prospective life and payments can only be made pursuant to a currently valid order, physicians must keep orders current at all times. They must also be retained by the supplier for immediate availability, should they be requested during medical review audits or for other purposes.

Replacing Oxygen Equipment - CMN Requirements

CMS implemented statutory provisions defining payment policy for home oxygen. Payment for oxygen equipment is made for a 36-month rental period. The supplier retains title to the equipment at the end of this rental period but is required to continue to provide the oxygen equipment and contents (when applicable) for the duration of the 5-year reasonable useful lifetime (RUL) of the oxygen equipment. The information below addresses the use of the oxygen CMN when replacing oxygen equipment.

If oxygen equipment is replaced because the RUL has been reached or due to irreparable damage, theft, or loss of equipment, the following is required:

Initial CMN (for replacement equipment)

• Initial Date should be the date that the replacement equipment is initially needed. This is generally understood to be the date of delivery of the oxygen equipment.
• Blood gas study - Repeat testing is not required. Enter the most recent qualifying value and test date. This test does not have to be within 30 days prior to the Initial Date. It could be the test result reported on the most recent prior CMN. (Suppliers are reminded that in an audit they may be asked to provide a copy of the actual test report to verify that coverage criteria have been met.)
• There is no requirement for a physician visit that is specifically related to the completion of the CMN.

Recertification CMN (for replacement equipment)

• Recertification Date should be 12 months following the Initial Date when the value on the Initial CMN (for the replacement equipment) meets Group I criteria or three months following the Initial Date when the qualifying blood gas value on the Initial CMN meets the Group II criteria. (Note: The Initial Date [for the replacement equipment] should be entered on the Recertification CMN.)
• Blood gas study: same instructions as for the Initial CMN for the replacement equipment.
• Physician visit: same instructions as for the Initial CMN for the replacement equipment.

Suppliers are reminded that a written order is required when replacing equipment. The CMN may act as a substitute for a written order if it meets the requirements for a detailed written order.

Claims for the initial rental month (and only the initial rental month) must have the RA modifier (replacement of DME item) added to the HCPCS code for the equipment when there is replacement due to RUL or replacement due to damage, theft, or loss. The RA modifier is effective for claims with DOS on/after 1/1/09. The RA modifier is not used when billing for a new initial following a 60+ day break in need. If replacing equipment before date of service 1/1/09, the RP modifier is used to signify "replacement."