HCPCS E1390: oxygen concentrator billing and the 36-month cap
E1390 is the HCPCS code for a stationary oxygen concentrator. Medicare pays it as a rental for up to 36 months, with a group modifier matching the qualifying test.
Written by Salman Saeed, CEO and Co-Founder · Reviewed by a Certified Medical Coder · Last reviewed October 2026In short: E1390 is paid as a monthly rental that includes oxygen contents, accessories and repairs, and it stops after 36 payments under 42 CFR 414.226. Initial claims from April 2023 use N1, N2 or N3 instead of KX.
What does HCPCS E1390 report?
E1390 is the HCPCS Level II code for a stationary oxygen concentrator with a single delivery port. Its long descriptor is "Oxygen concentrator, single delivery port, capable of delivering 85 percent or greater oxygen concentration at the prescribed flow rate".
E1391 is the dual-port version, used when two patients share one concentrator. E1392 is a portable concentrator rental. If a portable unit can also run as a stationary concentrator around the clock, policy article A52514 says E1390 is billed in addition to E1392.
| Item | Value |
|---|---|
| Added to HCPCS | January 1, 2000; no termination date in the October 2026 file |
| Pricing indicator | 33, oxygen and oxygen equipment |
| MUE, DME supplier table, October 1, 2026 | 1 (indicator 2, policy edit; rationale: code descriptor) |
| Written order prior to delivery | On the CMS Required List |
Who qualifies for a home oxygen concentrator?
LCD L33797, revised April 1, 2023, sorts patients into four groups. For Groups I and II the treating practitioner must have ordered and evaluated a qualifying blood gas study at the time of need, and oxygen in the home must be expected to improve the condition.
| Group | What the LCD requires |
|---|---|
| I | Arterial PO2 at or below 55 mm Hg or saturation at or below 88 percent at rest, awake, on room air; sleep and exercise variants also qualify |
| II | PO2 of 56 to 59 mm Hg or saturation of 89 percent, plus dependent edema suggesting heart failure, pulmonary hypertension or cor pulmonale, or hematocrit above 56 percent |
| III | No hypoxemia, but a condition shown in peer-reviewed literature to improve with oxygen, such as cluster headaches |
| IV | Denied: angina or dyspnea without hypoxemia, vascular desaturation without systemic hypoxemia, terminal illness not affecting breathing |
A supplier cannot perform or pay for the qualifying test. Exercise qualification needs three oximetry readings in one session. For a patient with sleep apnea, the qualifying saturation may only come from a titration sleep study after the apnea is treated; see E0601.
How does the 36-month rental cap work?
Under 42 CFR 414.226(a)(1), Medicare pays monthly rental for oxygen equipment for no longer than 36 months of continuous use. Article A52514 says that allowance covers contents, accessories, delivery, back-up equipment, maintenance and repairs.
| Period | Payment and duties |
|---|---|
| Months 1 to 36 | One monthly rental payment. The supplier of month one keeps supplying unless the patient moves or switches supplier. |
| Months 37 to 60 | No further rental payment during the 5-year useful lifetime, and the supplier of month 36 keeps furnishing the equipment. A concentrator maintenance visit is payable every 6 months, from 6 months after the rental ends. |
| Month 61 on | New equipment, if the patient elects it, starts a new 36-month period. |
Damage beyond repair, theft or loss starts a new 36-month period. So does a break in need of at least 60 days plus the rest of the month, with new medical necessity, but only inside the first 36 months. Repairs, upgrades and a change of supplier never restart it.
What order and retest rules apply to E1390?
E1390 is on the CMS Required Face-to-Face Encounter and Written Order Prior to Delivery List, which shows an effective date of October 28, 2026. A face-to-face encounter must happen, and a completed standard written order must reach the supplier on or before the delivery date and within six months after the encounter.
Delivery before the order is denied as not reasonable and necessary, even if the order arrives later (A52514). Group II and III patients also need a repeat qualifying test between the 61st and 90th day plus a new order; Group I has no formal retest. Payment stops until the retest is on file, then resumes at the same rental month.
How does E1390 sit on the claim?
A supplier reports E1390 in box 24D of the CMS-1500. For dates of service from April 1, 2023, an initial claim or a new 36-month period needs one group modifier, and KX on such a claim is rejected as invalid.
- N1, N2 or N3 for Group I, II or III, only if every criterion in the LCD for that group is met.
- GA with an ABN, GY for a statutory exclusion or GZ with no ABN when criteria are not met. A line with none of the required modifiers is rejected as missing information.
- Flow-rate modifiers: QE below 1 liter a minute, QG above 4, QF above 4 with portable oxygen, and QA, QB and QR for patients whose day and night rates differ. The rate at rest governs.
- RA on the first month of replacement equipment, with a narrative.
Under 42 CFR 414.226(g), the amount rises 50 percent above 4 liters a minute and falls 50 percent below 1. Purchased oxygen equipment is statutorily non-covered.
Which fields carry an oxygen concentrator rental?
E1390 goes in Item 24D with the group modifier that the page above describes for initial claims from April 2023, 1 unit in Item 24G for a month and the rental dates in Item 24A. Item 24E points to the lung or respiratory diagnosis. Item 17 carries the ordering physician, and for DME claims Chapter 26 puts the order-accepted location in Item 32.
Example: A patient starts home oxygen in October. The October line is E1390 with the initial-claim group modifier, pointer A (J44.9), 1 unit, $178.00, ordering physician in Item 17. A line that carries KX on an initial claim is rejected per the page above, so the field must be corrected and resubmitted.
Why do E1390 claims deny?
| Code | What X12 says | What usually causes it on E1390 |
|---|---|---|
| CO-50 | Non-covered because the payer does not deem it medically necessary | The test fits no group, was done by a supplier, or the day 61 to 90 retest is missing. |
| CO-4 | The procedure code is inconsistent with the modifier used | KX on an initial claim after April 1, 2023, where N1, N2 or N3 belongs. |
| CO-16 | Claim lacks information or has a billing error | No group or Q modifier, or a wrong flow-rate modifier. |
| CO-96 | Non-covered charge | Purchased equipment, or accessories used with patient-owned equipment. |
If these denials keep coming back, our denial management team can work them.
Related codes
- LCD L33797: Oxygen and Oxygen Equipment · CMS Medicare Coverage Database
- Policy Article A52514: Oxygen and Oxygen Equipment · CMS Medicare Coverage Database
- Article A55426: Standard Documentation Requirements for All Claims Submitted to DME MACs · CMS Medicare Coverage Database
- LCD L33718: Positive Airway Pressure (PAP) Devices · CMS Medicare Coverage Database
- Required Face-to-Face Encounter and Written Order Prior to Delivery List · CMS
- HCPCS quarterly update, October 2026 alpha-numeric file · CMS
- Medicare NCCI Medically Unlikely Edits, DME supplier services table, effective 10-01-2026 · CMS
- 42 CFR 414.226: Oxygen and oxygen equipment · eCFR
- 42 CFR 414.230: Determining a period of continuous use · eCFR
- Claim Adjustment Reason Codes · X12
- Medicare Claims Processing Manual, Chapter 26: Completing and Processing Form CMS-1500 Data Set · CMS
- Physician Fee Schedule relative value files, RVU26D (October 2026) · CMS
We check every rule, code and deadline against the official source. See our editorial policy.
Common questions
Straight answers from the team that does the work.
Ask a billing lead directly. A 20-minute call, Monday to Friday, 9am to 5pm Eastern.
01How do I bill an oxygen concentrator?
Bill E1390 once a month for up to 36 months, with N1, N2 or N3 on initial claims and any flow-rate modifier that applies. Contents, accessories, delivery and repairs are in that payment. The order must reach the supplier before delivery.
02What happens after month 36?
Medicare stops paying rental, but the supplier of month 36 must keep furnishing the equipment for the rest of its 5-year lifetime. Concentrator maintenance visits are payable every 6 months from 6 months after the rental ends. After year five, the patient may elect new equipment.
03What is the difference between E1390 and E1391?
E1390 has one delivery port. E1391 has two and is used when two beneficiaries use the same concentrator, and A52514 says it is billed for only one of them. Payment for contents is part of the stationary allowance for both codes.
04Can a patient on CPAP also get a home oxygen concentrator?
Yes, if both LCDs are met. For sleep apnea, a qualifying oxygen saturation may only come from a titration sleep study after the apnea is sufficiently treated. The chart must then show both the CPAP criteria and the oxygen criteria.
Oxygen claims denied on modifiers?
We check the group modifier, the flow rate and the order date before the monthly claim is sent.