Modifier N2

The Centers for Medicare and Medicaid Services (CMS) published a Medicare Learning Network article announcing the new N-modifiers for oxygen. The 3 new modifiers for home oxygen use under national coverage determination (NCD) 240.2 and the DME MAC Oxygen and Oxygen Equipment Local Coverage Determination (LCD) and LCD-related Policy Article (PA) were created to indicate the appropriate treatment regimen and presence of supporting documentation for each Medicare patient oxygen therapy group:

The new modifiers are effective January 1, 2023 and will be available in the April 2023 HCPCS code release.

Group II: Coverage is available for patients whose arterial PO2 is 56-59 mm Hg or whose arterial blood oxygen saturation is 89%, if there is:

  • Dependent edema suggesting congestive heart failure; or,
  • Pulmonary hypertension or cor pulmonale, determined by measurement of pulmonary artery pressure, gated blood pool scan, echocardiogram, or "P" pulmonale on EKG (P wave greater than 3 mm in standard leads II, III, or AVFL; or,
  • Erythrocythemia with a hematocrit greater than 56%.

In reviewing the arterial PO2 levels and the arterial oxygen saturation percentages specified above, the Medicare Administrative Contractors (MACs) must take into account variations in oxygen measurements that may result from such factors as the patient's age, the patient’s skin pigmentation, the altitude level, or the patient's decreased oxygen carrying capacity.


Last Updated Jan 16 , 2023