Evidence of Medical Necessity for Oxygen

Oxygen coverage is determined by the results of an arterial blood gas or oximetry test. A CMN for oxygen equipment must include results of specific testing before coverage can be determined.

Suppliers that bill electronically may transmit initial, revised, and recertification CMNs by electronic media using CMS-established standard formats. Information transmitted from a revised or recertification Form CMS-484 must accompany the first claim for monthly benefits submitted after the supplier has received the hard copy Form CMS-484 from the certifying physician. If the supplier submits Form CMS-484 information to the contractor electronically, the supplier must keep the paper certification readily available so that it may be promptly furnished to the contractor if requested for purposes of audits of medical necessity documentation.


Blood Oxygen Testing

The medical necessity of home oxygen is documented by the results of a blood oxygen test. The blood oxygen test may be either an arterial blood gas or an oximetry test. The following timeliness requirements must be met.


Initial Certification:

Groups I and II: Must be tested within 30 days prior to the date of initial certification. If the oxygen is begun immediately following discharge from an acute care facility, the test must be within two days prior to discharge.

Recertification:

Group I: Retesting requirements are to be determined by the contractor.

Group II: Must be retested between the 61st - 90th day after the date of the initial certification.



Revised Certifications:

Group I and II: Must be tested within 30 days prior to the date of the revised certification if the initial certification specified a length of need that is less than lifetime.

Physician Evaluation

Initial Certification:

Groups I and II: Must be seen and evaluated by the treating physician within 30 days prior to the date of initial certification
Recertifications:

Group I and II: Must be seen and re-evaluated by the treating physician within 90 days prior to any recertification date.