Does Medicare have any guidance for assigning modifier QF (prescribed amount of oxygen is greater than 4 LPM and portable oxygen is prescribed)?
If portable oxygen is prescribed, the fee schedule amount for portable equipment is added to the fee schedule amount for stationary oxygen rental. In addition to modifier QF, modifier QG (prescribed amount of oxygen is greater than 4 LPM) should be used to denote when the oxygen flow exceeds 4 liters per minute.
According to the Centers for Medicare & Medicaid Services in MM9848, modifier QF should be used in conjunction with claims submitted for stationary oxygen (codes E0424, E0439, E1390, or E1391) and portable oxygen (codes E0431, E0433, E0434, E1392, or K0738) when the prescribed amount of oxygen is greater than 4 LPM.
For more on this policy, go to https://www.cms.gov/Outreach-and-Education/Medicare-Learning-Network-MLN/MLNMattersArticles/Downloads/MM9848.pdf.