CMS-484

CERTIFICATE OF MEDICAL NECESSITY - Oxygen DME 484.5

Agency
CMS
Revision
12/18
Fillable fields
95
Pages
2
Official source
CMS form page
Checked
October 20, 2026
Fill CMS-484 online
Page 1 of form CMS-484

Form CMS-484: Certificate of Medical Necessity, Oxygen

Form CMS-484 is the Certificate of Medical Necessity (CMN) for oxygen from the Centers for Medicare & Medicaid Services (CMS), part of the U.S. Department of Health and Human Services. The form is printed as DME 484.3. Its instructions say the question section gathers clinical information to help Medicare determine the medical necessity for the items being ordered, and the CMS page notes the form is to be used starting January 1, 2007.

The form has four sections. Section A identifies the patient, supplier, place of service, procedure codes and physician, and may be completed by the supplier. Section B covers the estimated length of need, diagnosis codes and nine questions on oxygen test results, test conditions and flow rate, and may not be completed by the supplier. Section C describes the equipment and its cost, and Section D is the physician's attestation and signature.

The form says signature and date stamps are not acceptable. You can fill it out free in your browser on this page and download the result without an account.

Top of page 1 of Form CMS-484: Certificate of Medical Necessity, Oxygen, as printed by CMS

What's on Form CMS-484

Section A: certification type and date

Initial, revised and recertification dates. The instructions say a revised or recertified CMN always gives the initial date as well.

Section A: patient, supplier and physician

Patient and supplier details, place of service, facility name and address if applicable, supply item or service procedure codes, the patient's date of birth, sex, height and weight, and the physician's name, address, phone and UPIN or NPI.

Section B: length of need and diagnosis

Estimated length of need in months from 1 to 99, where 99 means lifetime, and diagnosis codes. The instructions ask for the primary code first, up to 4 codes.

Section B: questions 1 to 6

A recent arterial blood gas PO2 and/or oxygen saturation result and its date, where and under what condition the test was done, whether the patient is mobile within the home if portable oxygen is ordered, the highest flow rate in liters per minute, and a test on 4 LPM if more than 4 LPM is prescribed.

Section B: questions 7 to 9

Answered only if PO2 is 56 to 59 or oxygen saturation is 89 in question 1: dependent edema due to congestive heart failure, documented cor pulmonale or pulmonary hypertension, and a hematocrit greater than 56%.

Sections C and D

Section C: a narrative description of all items, accessories and options ordered, the supplier's charge and the Medicare fee schedule allowance for each. Section D: the physician attestation, signature and date.

How to complete Form CMS-484

  1. 1

    Supplier fills in Section A

    Enter the certification dates, patient and supplier details, place of service, procedure codes and physician information. The instructions say to use the qualifier XX before a 10-digit NPI.

  2. 2

    Supplier fills in Section C

    Describe the items, options, accessories, supplies and drugs ordered, with the supplier's charge and the Medicare fee schedule allowance for each, where applicable.

  3. 3

    Clinician answers Section B

    Enter the length of need and diagnosis codes, then answer the questions, checking Y for yes, N for no or D for does not apply. The form says to enter an X for a flow rate below 1 LPM.

  4. 4

    Physician reviews and signs

    The physician reviews Sections A, B and C, then signs and dates Section D. The form says signature and date stamps are not acceptable.

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Signing, claims and what the form says

Where it goes

The form does not print a submission address. The CMS address in the Paperwork Reduction Act notice is for comments on the form, and the form says not to submit claims to it. It points to medicare.gov for information on claim filing.

Revised and recertified CMNs

The instructions say a revised certification is completed when the physician changes the order based on the patient's changing clinical needs, and that the initial date is always given along with the revised or recertification date.

Signatures

Only the physician signs, in Section D. The form says signature and date stamps are not acceptable.

Accuracy statement

Section D says any falsification, omission or concealment of material fact in Section B may subject the physician to civil or criminal liability.

Identifier qualifiers

The instructions say to use XX before a 10-digit NPI, 1C before a legacy NSC number and 1G before a 6-digit UPIN.

Time to complete

The form estimates an average of 12 minutes per response, including reviewing the instructions and gathering the data. It shows OMB No. 0938-0679.

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Who uses Form CMS-484?

  • Suppliers

    The instructions say Section A may be completed by the supplier and Section C is to be completed by the supplier. The supplier gives its Medicare Supplier Number from the National Supplier Clearinghouse (NSC) or its NPI.

  • Treating physicians

    Section D is completed by the physician. The instructions say the signature certifies the CMN includes Sections A to D, the Section B answers are correct, Section A is correct, and the items ordered are medically necessary for this patient.

  • Other clinicians

    Section B may be completed by a non-physician clinician or a physician employee. The instructions say it is then reviewed, and the CMN signed, by the treating practitioner, and that person prints their name, title and employer.

  • Medicare patients

    The patient is the person the oxygen is ordered for. Section A records the patient's name, address, phone, Medicare ID as it appears on the Medicare card, date of birth, sex, height and weight. The form has no patient signature line.

The form splits the work between the supplier and the physician, section by section.

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Questions about Form CMS-484

Who fills out Form CMS-484?

The form splits it: the supplier may complete Section A and completes Section C, Section B may not be completed by the supplier, and the physician completes and signs Section D.

Can the supplier answer the Section B questions?

No. The form says Section B may not be completed by the supplier. A non-physician clinician or physician employee may complete it, but it is reviewed and the CMN signed by the treating practitioner.

When are questions 7 to 9 answered?

The form says to answer questions 7 to 9 only if the PO2 is 56 to 59 or the oxygen saturation is 89 in question 1.

What if the flow rate is less than 1 LPM?

Question 5 asks for the highest oxygen flow rate ordered in liters per minute, and says to enter an X if it is less than 1 LPM.

What does 99 mean for the length of need?

The form says 99 means lifetime. The instructions say to enter 99 if the patient will need the item for the rest of their life.

Can the physician use a signature stamp?

No. The form says signature and date stamps are not acceptable.

Can claims be sent to the address on the form?

No. The form says not to submit claims to the CMS address in its Paperwork Reduction Act notice, and points to medicare.gov for information on claim filing.