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Oxygen FAQs

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Is an initial F2F evaluation required?
- While there's no formal requirement in the NCD or LCD, good medical practice would dictate some type of F2F or telehealth evaluation prior to ordering oxygen.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Since Oxygen is considered a drug in most states and requires an annual prescription, would an annual prescription meet the continued need requirement?
- Yes; Once initial medical need and continued payment requirements specified in the Oxygen LCD and Policy Article are met, a new order would be acceptable to meet continued medical need moving forward until month 60. See Question #3 for requirements once RUL is reached.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
What is needed once the reasonable useful lifetime (RUL) is reached for continued payment of oxygen?
- Once the RUL is reached, there is no new testing or face-to-face/telehealth examination required; however, a new order is required.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
For Group II or Group III, how does a supplier indicate that a re-evaluation occurred between the 61st and 90th day? Should this documentation just be available upon request?
- For Group II and III patients, there must be documentation in the medical record to support that the treating practitioner evaluated the results of a follow-up blood gas study performed between the 61st and 90th day after initiating oxygen therapy. The medical records must be available upon request and the KX modifier must be billed on the claim if all coverage criteria are met. The KX modifier must not be used if criteria are not met. Note: Effective for new oxygen rental periods beginning on or after April 1, 2023, the N1, N2, or N3 modifiers will be billed in place of the KX modifier. Oxygen rentals that began prior to April 1, 2023 may continue to be billed with the KX modifier for the remainder of the rental period and for subsequent billing of oxygen contents or maintenance and service.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
For a beneficiary that qualifies for oxygen based on Group I criteria but with a length of need less than lifetime, what is required to extend the length of need?
- A new order is necessary to confirm continued medical need. There is no requirement for retesting or re-evaluation of the test results. Information regarding length of need will be determined by documentation in the beneficiary's medical record. For beneficiaries with an acute condition that qualify for oxygen, the supplier is obligated to maintain close communication with the beneficiary and the treating practitioner to determine length of need. Suppliers are reminded that Medicare will only pay for items/services that are reasonable and necessary. Once the acute need is resolved, depending on co-existing chronic conditions, the oxygen may no longer be reasonable and necessary.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Will a CMN or DIF dated prior to January 1, 2023, still be sufficient to show continued need/use, once CMNs are eliminated?
- Yes, a CMN (initial, recert, revised) obtained prior to 1/1/23 will be good for one (1) year from the initial, recertified, or revised date on the CMN.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
If the N3 modifier for Oxygen is used, will the claim automatically deny, or will it suspend for review?
- The N-modifiers will be required in place of the KX modifier for new oxygen rental periods beginning on or after April 1, 2023. The N3 modifier will be used to identify patients with normal (i.e., ≥90%) oxygen levels who qualify based on their specific diagnosis (e.g., cluster headaches).
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Clarification is needed on the timeframe of need for OSA patients requiring Oxygen. The 30-day timing requirement has been removed from the Oxygen LCD; the new requirement is at "the time of need". We are still experiencing back-ups with sleep labs. Will this be an issue if the evaluation that describes the possible need for overnight oxygen for an OSA patient is one or two months prior to the in-lab titration? Will the titration testing and the order be considered "the time of need" or would a new evaluation be required?
- For the beneficiary with OSA, the "time of need" would result from a qualifying test conducted during the in-lab diagnostic or titration polysomnogram (PSG). As noted in the Oxygen LCD:
  
  In the case of OSA, it is required that the OSA be appropriately and sufficiently treated before oxygen saturation results obtained during sleep testing are considered qualifying for oxygen therapy and oxygen equipment (see Positive Airway Pressure (PAP) Devices for the Treatment of Obstructive Sleep Apnea LCD for additional information).
  
  As a result of the requirement above, "time of need" may only be determined once the OSA has been appropriately and sufficiently treated. This, by definition, takes place during the diagnostic or titration PSG.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
A patient with cluster headaches will be included in Group III and will require a follow up evaluation between the 61st and 90th days after the initiation of therapy. At the time of that follow up evaluation if the physician writes an order for an additional 3 months, then would another evaluation need to occur at that time? Would a new evaluation be required until the physician writes an order for 99 months?
- A follow-up beneficiary evaluation between the 61st and 90th day after initiation of therapy is not required; an evaluation of a repeat blood gas study is required. Statutory requirement §1834(a)(5)(E) requires a beneficiary in Group III have a repeat blood gas study between the 61st and 90th day after initiating therapy. This test result must be evaluated by the treating practitioner to reaffirm the medical need for the oxygen. There is no requirement for any additional testing or re-evaluation after the statutory reaffirmation of need. However, continued medical need should be documented at least every 12 months consistent with the Standard Documentation Requirement Policy Article.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Patient has pneumonia with a 2-month medical need then oxygen is returned but 7 months later develops another acute condition and needs oxygen for 3 months. How do we communicate the new initial need? Do we add narratives for every "new need" and does a new 36-month count start over each time?
- Standard oxygen payment rules apply. In this example, a new 36-month period would start for the new episode of need.
  
  Unless there is a break in medical necessity that lasts longer than 60 consecutive days plus the days remaining in the rental month in which use ceases, medical necessity is presumed to continue.
  
  If an interruption in the use of equipment continues for more than 60 consecutive days plus the days remaining in the rental month in which use ceases, a new rental period begins if the supplier submits all of the following information:
  1. A new prescription.
  2. New medical necessity documentation.
  3. A statement describing the reason for the interruption and demonstrating that medical necessity in the prior episode ended.
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Overall, what will audit contractors be looking for in the medical record for those patients in Group III? Is an initial F2F evaluation required? (LCD only references evaluation of test results)
• Evidence of an evaluation of the qualifying test results. What type of documentation are you looking for? The lab values are often a separate document in a record and ordering MD doesn't document they evaluated the lab result in as many words.
• Provision in the LCD that provision of oxygen will improve patient's condition, how will audit contractors evaluate this?
- A blood gas study is necessary to show the absence of hypoxemia. Additionally, the DME MACs would look for documentation to see if oxygen provided will improve the beneficiary condition. There must be a documented medical condition with distinct physiologic, cognitive, and/or functional symptoms published in high-quality, peer-reviewed literature to be improved by oxygen therapy, such as cluster headaches (not all inclusive). The DME MACs cannot speak for other auditing contractors.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Once a patient is eligible for Medicare, what will be required from switching from either managed care, Medicaid, or Medicare advantage plan?
- Is new testing required:
  - When a patient changes from managed care, Medicaid or Medicare Advantage to FFS?
    
    Response: There is a long-standing policy in Medicare that to get an item under Medicare, you must meet Medicare’s requirements at the time of the first claim when under Medicare eligibility. The beneficiary does not have to obtain a new blood gas study, but the test must be the most recent qualifying study the beneficiary obtained previously and under the guidelines specified in DME MAC policy.
  - When a patient is requalified for oxygen after their previous equipment met its 5-year useful lifetime?
    
    Response: No.
  - How long is testing acceptable? For example, if a patient was tested but opted not to receive oxygen at that time and oxygen was prescribed at a later date, for what period of time may the original testing be used?
    
    Response: Coverage of oxygen is based on testing conducted at time of need. The beneficiary may need to be retested to determine that oxygen is medically reasonable and necessary depending on circumstances documented in the medical records to explain why the oxygen was not needed at the time of original testing.
  - Would blood gas or saturation tests taken in the ER qualify?
    
    Response: Yes.
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
What if a Group II patient wasn't re-evaluated and a repeat blood gas test was not done between the 61st and 90th day but was done after the 90th day? Can we just pick up billing after they have retested and been re-evaluated?
- Yes, if the repeat blood gas study and/or re-evaluation is not completed during the 61st and 90th day, but is subsequently completed, coverage may resume on the date of completion.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
The LCD states that testing needs to be reviewed in the treating practitioner visit. If the patient has a visit 1/2/23 and the 6-minute walk test (6MWT) is booked for 1/25/23 does the patient need another visit to have these results discussed after?
- The time of need would be based on the 6MWT and the treating practitioner's interpretation and evaluation of that test. The treating practitioner is not required to have an in-person/telehealth visit following the 6MWT and may communicate with the beneficiary, at their discretion, the results of that test.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Should we cease billing the portable unit when the patient exceeds 4LPM and they have a stationary unit? I realize we will not get paid for the portable unit because we are getting 50% more for the stationary unit along with the applicable modifier.
- No, both the portable and stationary units should be billed with the appropriate modifier to indicate high liter flow. The additional allowance for high liter flow will be split between the stationary and portable units consistent with the CMS instructions outlined in Change Request 10158.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Can the oximetry testing be performed by a visiting nurse and the evaluation from the physician be completed through a telehealth visit?
- The qualifying blood gas study must be one that complies with the Fiscal Intermediary, Local Carrier, or A/B Medicare Administrative Contractor (MAC) policy on the standards for conducting the test and is covered under Medicare Part A or Part B. This includes a requirement that the test be performed by a provider who is qualified to bill Medicare for the test – i.e., a Part A provider, a laboratory, an Independent Diagnostic Testing Facility (IDTF), or a treating practitioner. The treating practitioner must evaluate the results of a qualifying blood gas study and document the need for the oxygen within the beneficiary's medical record. A telehealth visit would be an acceptable method for the treating practitioner to document the requirements are met.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Can we use documentation of a telehealth visit to document the need for oxygen? Is an actual face-to-face visit required?
- There is no formal requirement for a face-to-face/telehealth visit in the NCD or LCD. The NCD and LCD require that a treating practitioner evaluate and document the results of a qualifying blood gas study.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
If a physician orders oxygen for a patient in Group I with an acute condition and does not specify how long the oxygen will needed, will coverage be there for one year?
- Information regarding length of need will be determined by documentation in the beneficiary's medical record. For beneficiaries with an acute condition that qualify for oxygen, the supplier is obligated to maintain close communication with the beneficiary and the treating practitioner to determine length of need. Suppliers are reminded that Medicare will only pay for items/services that are reasonable and necessary. Once the acute need is resolved, depending on co-existing chronic conditions, the oxygen may no longer be reasonable and necessary.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Is there a mandatory length of need that the patient must need oxygen? (i.e. patient only needs oxygen for 1 month.)
- Length of need must be supported in the medical records. However, there is not a specified minimum length of need required.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
If a patient goes to doctor and they order oxygen testing at an outpatient facility, does the patient have to go back to the doctor after the testing is done to document test results?
- The medical records must document the testing that demonstrates medical need. There is not a requirement for a face-to-face evaluation with the practitioner after the testing is completed. That is at the discretion of the provider. However, there must be documentation in the beneficiary's medical record that the provider evaluated the testing performed at the time of need.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
After patients get re-evaluated and testing for Groups II and III – do we have to do re-testing every year? Or do they only need to do that within the 61st-90th day?
- For beneficiaries who meet Group II or Group III criteria for their oxygen needs, retesting and re-evaluation of the test result by the treating practitioner is required between the 61st and 90th day. Only documentation of continued medical need is necessary thereafter.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
If a patient is doing an overnight pulse oximetry to qualify for nocturnal oxygen, if their baseline is 100% and they de-sat to 95% that would qualify them for nocturnal oxygen?
- Per criterion 3 for Group I: A decrease in arterial PO2 more than 10 mm Hg, or a decrease in arterial oxygen saturation more than 5 percent from baseline saturation, taken during sleep and associated with symptoms of hypoxemia such as impairment of cognitive processes and nocturnal restlessness or insomnia (not all inclusive). In this instance, oxygen and oxygen equipment is only reasonable and necessary during sleep.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Can a beneficiary qualify for oxygen based on the oxygen SAT results obtained during a polysomnogram if the patient is found not to have OSA during that study or can the titration polysomnogram results only be used for patients that do have OSA?
- The test result obtained during a diagnostic polysomnogram would be acceptable for beneficiaries in whom OSA has been ruled out. Results from a titration polysomnogram may be acceptable once the OSA has been sufficiently treated to qualify for oxygen, assuming all other requirements outlined in the Oxygen LCD are met.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Does the medical record need to contain the oxygen liter flow if it's listed on the SWO. What if they conflict?
- Yes, the liter flow should be in the medical records. In the case of conflict, the medical record will be used.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
Do patients with Central Sleep Apnea (CSA) require a titration polysomnogram to qualify for oxygen during sleep?
- Although not specifically required in the Respiratory Assist Devices LCD, similar to OSA, one would expect that the CSA be sufficiently treated before a qualifying oxygen test is obtained.
  
  Originally published: 02.17.2023
  Reviewed: 12.08.2025
If the beneficiary’s medical record reflects “suspected” obstructive sleep apnea (OSA), could they still qualify for nocturnal oxygen via an overnight pulse oximetry?
- Yes, nocturnal oxygen would be considered for coverage based on an overnight pulse oximetry for beneficiaries with suspected OSA. If the beneficiary had confirmed OSA, a titration polysomnogram would be required to qualify for oxygen during sleep.
  
  Originally published: 09.22.2025
  Reviewed: 12.08.2025
How would a beneficiary qualify for coverage of oxygen for the treatment of hypoxemia during sleep when they are using an oral appliance or implanted hypoglossal nerve stimulator (instead of a CPAP device) in the treatment of their obstructive sleep apnea (OSA)?
- For beneficiaries with OSA, a qualifying oxygen saturation test may only occur during a titration polysomnographic study (either split night or stand-alone). An oral appliance or hypoglossal nerve stimulator can be worn during the titration instead of a CPAP device. The results of the titration polysomnogram will determine if the oxygen test is qualifying.
  
  Originally published: 01.14.2026

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Oxygen FAQs

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