HCPCS code E1390: Oxygen Concentrator, Single Delivery Port (≥85% O₂)

## **Documentation requirements** To bill for an oxygen concentrator, comprehensive documentation is essential to demonstrate medical necessity. Here's what's typically required: - **Face-to-face evaluation and written physician order**: A face-to-face evaluation and detailed written order (DWO) from the treating physician is mandatory. The order must include the patient's name, the item being prescribed (oxygen concentrator), the specific flow rate (e.g., liters per minute), the frequency and duration of use, and the duration of need. - **Medical records**: The patient's medical records must support the need for oxygen therapy. This includes a diagnosis of a severe lung disease or other conditions leading to hypoxemia. - **Qualifying clinical test**: A qualifying blood gas study, such as an arterial blood gas (ABG) test or a pulse oximetry (SpO2) test, must be performed and documented. This test must show that the patient meets the criteria for hypoxemia as defined by the payer's policy (e.g., Medicare's Group I or Group II criteria). These tests must be performed while the patient is in a chronic, stable state, not during an acute illness. In addition, the documentation must demonstrate that a portable oxygen device (if also used) does not fulfill the patient’s continuous oxygen needs, justifying a stationary unit. - **Continued need**: For ongoing coverage, documentation must show a continued medical need for the oxygen equipment. This often involves a physician recertification and additional testing after a certain period, as well as a refill order or a recent change in prescription.

## **Billing requirements** Billing for E1390 is a multi-step process with specific rules, particularly for Medicare. - **Rental period**: According to the Centers for Medicare and Medicaid Services (CMS), Medicare typically pays for oxygen concentrators on a rental basis for a continuous 36-month period. The monthly payment for E1390 covers the equipment, supplies, accessories, and maintenance. - **Modifiers**: Modifiers are crucial for accurate billing and reimbursement. Note that use of the N3 modifier may denote that coverage criteria have been met—CMS leads may audit these claims via pre-pay review processes. - **Maintenance and service**: Maintenance and servicing claims for portable oxygen equipment should not be billed under E1390; they require the correct code. Notably, only one maintenance visit per six-month period is payable across stationary or portable devices. While ventilation of the concentrator may occur in multiple locations (home, travel, etc.), only one repair or service per six months is rechargeable.

## **Other relevant codes** - **E1391**: Oxygen concentrator with dual delivery ports, same oxygen criteria as E1390. - **E1392**: Portable oxygen concentrator, rental - **E1352**: Oxygen accessory, flow regulator capable of positive inspiratory pressure - **E1358**: Oxygen accessory, DC power adapter for portable concentrator, any type, replacement only - **E0433**: Portable liquid oxygen system, rental; home liquefier used to fill portable liquid oxygen containers, includes portable containers, regulator, flowmeter, humidifier, cannula or mask and tubing, with or without supply reservoir and contents gauge - **E0455**: Oxygen tent, excluding croup or pediatric tents