Indications Home oxygen is covered only if all the following conditions are met: The treating physician has determined that the patient has a severe lung disease hypoxia-related symptoms that might be expected to improve with oxygen therapy, and - The patient's blood gas study meets the criteria for oxygen therapy (see below), and
- The patient's blood gas study was performed by a physician or by a qualified provider or supplier of laboratory services, and
- The qualified blood gas study was obtained under the following conditions:
If the qualifying blood gas study is performed during an inpatient hospital stay, the reported test must be the one obtained closest to, but no earlier than 2 days prior to the discharge date, or - If the qualifying blood gas study is not performed during an inpatient hospital stay, the reported test must be performed while the patient is in a chronic stable state, e.g., not during a period of acute illness or an exacerbation of their underlying disease, and
- Alternative treatment measures have been tried or considered and deemed clinically ineffective.
The patient must be seen and evaluated by the treating physician within 30 days prior to the date of the Initial Certification. The patient must be seen and reevaluated by the treating physician within 90 days prior to the date of any Recertification. If the patient is not seen and reevaluated within 90 days prior to Recertification but is subsequently seen, payment can be made for dates of service between the scheduled Recertification date and the physician visit date if the blood gas study criteria are met.
Medicare will deny as not medically necessary any claim for patients that have any of the following conditions: - Angina pectoris in the absence of hypoxemia.
- Dyspnea without cor pulmonale or evidence of hypoxemia.
Severe peripheral vascular disease resulting in clinically evident desaturation in one or more extremities but in the absence of systemic hypoxemia.
Terminal illnesses that do not affect the respiratory system.
The qualifying blood gas study must be performed by a physician or by a qualified Medicare Part A provider or a qualified laboratory. A DME supplier is not considered a qualified provider or a qualified laboratory for purposes of providing oxygen to Medicare patients. In addition, the qualifying blood gas study may not be paid for by any supplier. For sleep oximetry studies, the oximeter provided to the patient must be tamper-proof and must have the capability to download data that allows documentation of the duration of oxygen desaturation below a specific value. For patients who qualify for oxygen coverage based only on sleep oximetry study, the oxygen saturation value reported in question 1b of the Oxygen CMN must be the lowest value (not related to artifact) during the 5 minute qualifying period reported on the sleep oximetry study. A report of the sleep studying documenting the qualifying desaturation must be available to the DMERC on request. The qualifying blood gas study may be performed while the patient is on oxygen as long as the reported blood gas values meet the Group I or Group II criteria. For Initial Certification, the blood gas study reported on the CMN must be the most recent study obtained prior to the Initial Date indicated in Section A of the CMN and this study must be obtained within 30 days a prior to that Initial Date. There is an exception for patients who were on oxygen in a Medicare HMO and who transition to fee-for-service Medicare. For those patients, the blood gas study does not have to be obtained 30 days prior to the Initial Date, but must be the most recent test obtained while in the HMO. For patients initially meeting Group I criteria, the most recent blood gas study prior to the 13th month of oxygen therapy must be reported on the recertification CMN. For patients initially meeting Group I criteria, if the estimated length of need on the Initial CMN is less than lifetime and the physician wants to extend coverage, a repeat blood gas study must be performed within 30 days prior to the date of the Revised Certification. For patients initially meeting Group II criteria, the most recent blood gas study that was performed between the 61st and 90th day following initial certification must be reported on the Recertification CMN. (An exception would be situations in which the initial test was performed at rest/awake and on room air and the most recent test was performed on oxygen and was non-qualifying. In those situations, report the most recent at rest/awake test on room air. If a qualifying test is not performed between the 61st and 90th day of home oxygen therapy, but the patient continues to use oxygen and a test is obtained at a later date, if that test meets Group I or II criteria, coverage would resume beginning with the date of that test. For patients initially meeting Group II criteria, if the estimated length of need on the Initial CMN is less than lifetime and the physician wants to extend coverage, a repeat blood gas study must be performed within 30 days prior to the date of the Revised Certification. For any Revised CMN, the blood gas study reported on the CMN must be the most recent test performed prior to the Revised date. When both arterial blood gas (ABG) and oximetry tests have been performed on the same day under the same conditions, report the PaO2 on the CMN. If the PaO2 at rest/awake is non-qualifying, but an exercise or sleep oximetry test on the same day is qualifying, the oximetry test result will determine coverage. Group I criteria include any of the following: An arterial PaO2 at or below 55 mm Hg or an arterial oxygen saturation at or below 88% taken at rest (awake), or
An arterial PaO2 at or below 55 mm Hg, or an arterial oxygen saturation at or below 88%, for at least 5 minutes taken during sleep for a patient who demonstrates an arterial PaO2 at or above 56 mm Hg or an arterial oxygen saturation at or above 89% while awake, or
A decrease in arterial PaO2 more than 10 mm Hg, or a decrease in arterial oxygen saturation more than 5%, for at least 5 minutes taken during sleep associated with symptoms or signs reasonably attributable to hypoxemia, or
An arterial PaO2 at or below 55 mm Hg or an arterial saturation at or below 88%, taken during exercise for a patient who demonstrates an arterial PaO2 at or above 56 mm Hg or an arterial oxygen saturation at or above 89% during the day while at rest. In this case, oxygen is provided for during exercise if it is documented that the use of oxygen improves the hypoxemia that was demonstrated during exercise when the patient was breathing room air.
Initial coverage for patients meeting Group I criteria is limited to 12 months or the physician-specified length of need, whichever is shorter. Group II criteria include the presence of (a) an arterial PaO2 of 56 - 59 mm Hg or an arterial blood oxygen saturation of 89% at rest (awake), during sleep for at least 5 minutes, or during exercise (as described under Group I criteria) and (b) any of the following: - 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, or
- Erythrocythemia with a hematocrit greater than 56%.
Initial coverage for patients meeting Group II criteria is limited to 3 months or the physician-specified length of time, whichever is shorter.
Group III includes patients with arterial PaO2 levels at or above 60 mm Hg or arterial blood oxygen saturations at or above 90%. For these patients there is a rebuttable presumption of noncoverage. Most companies will not accept Group III patients because they are more often then not denied. For all the sleep oximetry criteria described above, the 5 minutes does not have to be continuous. A portable oxygen system is covered if the patient is mobile within the home and the qualifying blood gas study was performed while awake and at rest or during exercise. If the only qualifying blood gas study was performed during sleep, portable oxygen will be denied. If portable oxygen system is covered, Absolute Respiratory Care must provide whatever quantity of oxygen the patient uses; Medicare's reimbursement is the same, regardless of the quantity of oxygen dispensed. In addition a portable oxygen system can be used either by itself or in addition to a stationary oxygen system. Portable oxygen is not covered when it is provided only as a backup to a stationary oxygen system. If basic oxygen coverage criteria have been met, a higher allowance for a stationary system for a flow rate of greater than 4 LPM will be paid only if a blood gas study performed while the patient is on 4 LPM meets Group I or II criteria. If a flow rate greater than 4 LPM is billed and the coverage criterion for the higher allowance is not met, payment will be limited to the standard fee schedule. If a patient qualifies for additional payment for greater than 4 LPM of oxygen and also meets the requirements for portable oxygen, payment will be made for either the stationary system (at the higher allowance) or the portable system (at the standard fee schedule allowance for a portable system). So basically you cannot bill for a portable system if Absolute Respiratory Care is receiving the higher allowable for a stationary system with a flowrate of 4 LPM or greater. Oxygen contents are included in the allowance for rented oxygen systems. Stationary oxygen contents (E0441, E0442) are separately payable only when the coverage criteria for home oxygen have been met and they are used with a patient-owned stationary gaseous or liquid system. Portable contents (E0443, E0444) are separately payable only when the coverage criteria for home oxygen have been met and: The beneficiary owns a concentrator and rents or owns a portable system, or
The beneficiary rents or owns a portable system and has no stationary system (concentrator, gaseous, or liquid).
If the criteria for separate payment of contents are met, they are separately payable regardless of the date that the stationary or portable system was purchased. Oxygen accessories, including but not limited to, transtracheal catheters (A4608), cannulas (A4615), tubing (A4616), mouthpieces (A4617), face tent (A4619), masks (A4620, A7525), oxygen conserving devices (A9900), oxygen tent (E0455), humidifiers (E0555), nebulizer for humidification (E0580), regulators (E1353), and stand/rack (E1355) are included in the allowance for rented systems. Absolute Respiratory Care must provide any accessory ordered by the physician. Accessories are separately payable only when they are used with a patient-owned system that was purchased prior to June 1, 1989. Accessories used with a patient-owned system that was purchased on or after June 1, 1989 will be denied as noncovered. If a beneficiary travels outside of Absolute Respiratory Care's usual service area, it is the beneficiary's responsibility to arrange for oxygen during their travels. Medicare will only pay one supplier for oxygen during any one rental month. In the real world this doesn't happen. In a competitive market, such as the one existing today, it is in Absolute Respiratory Care's best interest to handle their patient's oxygen needs. Arranging for oxygen while traveling is a big marketing campaign by nationwide suppliers. Arranging your patient's travel oxygen and keeping them as a happy customer by not making them pay for it can help them to be a loyal customer and can provide positive references for Absolute Respiratory Care. The only exception to this rule is airplane oxygen. Medicare actually states that any oxygen recieved from the airlines is the responsibility of the beneficiary. You may give them some concessions for performing this task, but airlines will not bill you for their services and will expect cash on delivery. Only rented oxygen systems (E0424, K0738, E0431, E0434, E0439, E1390RR) are eligible for coverage. Purchased oxygen systems (E0425, E0430, E0435, E0440, E1390NU, E1390UE) will be denied as noncovered. Emergency or standby oxygen systems will be denied as not medically necessary since they are precautionary and not therapeutic in nature. Oximeters (E0445) and replacement probes (E4606) will be denied as noncovered because they are monitoring devices that provide information to physicians to assist in managing the patient's treatment. Respiratory therapists' services and topical hyperbaric oxygen chambers (A4575) are noncovered under the DME benefit. Clinical TrialsOxygen is covered for patients who are enrolled subjects in clinical trials approved by CMS and sponsored by the National Heart, Lung, and Blood Institute (NHLBI) and who have an arterial PO 2 from 56 to 65 mmHg or an oxygen saturation at or above 89%. The additional Group 2 coverage criteria do not apply to these patients. Documentation RequirementsIn addition to a "Standard" prescription, a Certificate of Medical Necessity (CMN) CMS form 484 (DME form 484.03) must be filled out signed and dated by the ordering physician. The CMN may act as a substitute for a written order if it is sufficiently detailed. The CMN must be kept on file by Absolute Respiratory Care. The Initial CMN must be sent along with the first claim to Medicare. The initial CMN certifications have been detailed above, the recertification CMNs are good for a lifetime, if so designated. The recertification CMN is sent by making sure there is the "Initial" and "Recertification" date marked on the CMN form. If Absolute Respiratory Care is a new supplier for a patient already receiving Medicare oxygen, they must be able to provide the DMERC with an original CMN on request. (An original CMN is a CMN that has a physician's original signature on it. It is not necessarily an Initial CMN or the first CMN for that patient.) If Absolute Respiratory Care obtains a new CMN, it would be considered a Revised CMN. In this situation, if the oxygen order is the same, the CMN does not have to be submitted with the claim. A new CMN is required: 3 months after Initial Certification (i.e., with the fourth month's claim) if oxygen results on the Initial Certification are in Group II. The blood gas study reported must be the most recent study that was performed between the 61st and 90th day following the Initial Date.
When a Group I patient with a length of need less than or equal to 12 months was not retested prior to Revised Certification/Recertification, but a qualifying study was subsequently performed. The Initial Date on this new CMN is the date of the subsequent qualifying blood gas study.
In other situations at the discretion of the DMERC. The blood gas study reported must be the most recent study that was performed within 30 days prior to the Recertification Date.
When an Initial CMN does not meet coverage criteria and the patient was subsequently retested and meets coverage criteria. The Initial Date on this new CMN is the date of the subsequent qualifying blood gas study.
When there was a change of supplier due to an acquisition and the previous supplier did not file a recertification when it was due and the requirements for the recertification were not met when it was due. The Initial Date on this new CMN is the date of the subsequent qualifying blood gas study. A revised CMN is required: When the prescribed maximum flowrate changes from one of the following categories to another: (a) less than 1 LPM, (b) 1 - 4 LPM, (c) greater than 4 LPM. If the change is from category (a) or (b) to category (c), a repeat blood gas study with the patient on 4 LPM must be performed within 30 days prior to the start of the greater than 4 LPM flow.
When a portable oxygen system is added subsequent to Initial Certification of a stationary system. In this situation, there is no requirement for a repeat blood gas study unless the initial qualifying study was performed during sleep, in which case a repeat blood gas study must be performed while the patient is at rest (awake) or during exercise within 30 days prior to the Revised date.
When the length of need expires — if the physician specified less than lifetime length of need on the most recent CMN. In this situation, a revised blood gas study must be performed within 30 days prior to the Revised Date.
When there is a new treating physician but the oxygen order is the same. In this situation, there is no requirement for a repeat blood gas study. Note: In this situation, the Revised CMN does not have to be submitted with the claim but must be kept on file by the supplier.
When a stationary system is added subsequent to Initial Certification of a portable system. In this situation, there is no requirement for a repeat blood gas study.
If a Group I patient with a lifetime length of need was not seen and evaluated by the physician within 90 days prior to the 12 months Recertification but was subsequently seen, the date on Recertification CMN should be the date of the physician visit. If there was a change of supplier due to an acquisition and the previous supplier did not file a recertification when it was due but all the requirements for the recertification were met when it was due, a Recertification CMN would be filed with the recertification date being 12 or 3 months after the Initial Date depending on whether the Initial Certification was based on Group I or Group II criteria. A new prescription, not a CMN or blood gas, is required: Prescribed flowrate changes but remains one of the following categories: (a) less than 1 LPM, (b) 1 - 4 LPM, (c) greater than 4 LPM.
Change from one type of system to another (i.e., concentrator, liquid, gaseous).
When a patient changes from Medicare secondary to Medicare primary coverage.
When Absolute Respiratory Care changes the assignment status on a submitted claim.
The appropriate HCPCS code modifiers must be used with stationary gaseous (E0424), liquid systems (E0439), portable gaseous oxygen system (K0738) or an oxygen concentrator (E1390): QE if the prescription is less than 1 LPM.
QF if the prescription is for greater than 4 LPM and portable oxygen is prescribed.
QG if the prescription is for greater than 4 LPM and portable oxygen is not prescribed.
QH if an oxygen-conserving device is being used. | 
