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Regulatory: Watch out for MAC instructions

Regulatory: Watch out for MAC instructions

Q. When can oxygen suppliers stop using the CMN? 

A. Suppliers can stop using CMNs for oxygen setups with dates of service on and after Sept. 27, 2021. A recent change to the Home Use of Oxygen National Coverage Determination (NCD) eliminates the CMN requirement. In lieu of a CMN, suppliers need a standard written order from a treating practitioner.  

To release initial claims for hypoxic patients, suppliers must confirm the medical records support the need for oxygen with test results at or below 89% SAT or 59 mmHg ABG. For acute and short-term conditions, these documents support billing for the lesser of the prescribed length of need or 120 days before requiring renewal. For chronic and long-term conditions, documents support billing for up to 12 months before requiring renewal.  

CMS suspended traditional oxygen LCD requirements during the pandemic to allow payment for scenarios that subsequently made their way into the final NCD. These temporary claim processing instructions remain in effect and suppliers can use the CR modifier and COVID-19 narrative – even if the patient does not have a COVID diagnosis - to ensure oxygen claims process properly without a CMN.  

The answer is slightly more complicated for orders dated prior to Sept. 27 or for those with non-hypoxic test results. Although the expanded provisions of the finalized NCD took effect immediately, the MACs need time to modify the claims processing system, update LCDs and policy articles, and supplement the NCD guidance. We expect the forthcoming DME MAC instructions will specify if and how CMN elimination applies to setups initiated prior to the NCD change, what the contractors will require for renewal, and how the MACs will use discretion to evaluate non-hypoxic documentation. Until the MACs release further instructions, suppliers who forgo CMNs for aged and non-hypoxic orders should hold those claims.  

Andrea Stark is the founder and head of reimbursement at MiraVista, LLC. You can reach her at  


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