HCPCS Code K0738: Portable Gaseous Oxygen System, Rental – Home Compressor to Fill Portable Cylinders

## **K0738 documentation requirements** Accurate, policy-aligned documentation will assist providers in establishing eligibility and supporting continued payment. The following elements summarize complete information expected in the record. ### **Qualifying test at time of need** Document qualifying blood gas or pulse oximetry at the time of need, consistent with the oxygen coverage groups. Record hypoxemia for Group I or II, or document a normoxemic medical condition that improves with oxygen therapy when applicable. Include the treating practitioner’s evaluation of the results. ### **Treating practitioner order and standard written order** Maintain a signed prescription and a valid standard written order specifying oxygen modality, flow rate, frequency, and need for portability. When required by current CMS lists, ensure a face-to-face encounter and a written order prior to delivery are on file before furnishing the item. ### **Initial and continued payment evidence by coverage group** For Group I, confirm that therapy remains reasonable and necessary. For Group II and Group III, include a repeat qualifying blood gas test between days 61 and 90 after initiation and a new order at that interval. Reimbursement ends if continued payment requirements are not met, and it resumes at the prior month in the rental cycle once requirements are satisfied. ### **Delivery, setup, and education records** Keep contemporaneous proof of delivery signed by the patient or caregiver, or carrier confirmation for shipment. Document setup, training on safe home use to fill portable oxygen cylinders, and confirmation that all components and accessories were provided, including the regulator, flowmeter, humidifier, cannula or mask, and tubing. ### **Ongoing need and usage** Record ongoing medical need, adherence, and any changes in flow rate or mobility requirements. Note any equipment changes ordered by the practitioner, and track maintenance interactions when applicable within months 37–60.

## **K0738 billing requirements** K0738 follows Medicare’s oxygen payment framework. The points below highlight what billers must capture for compliant claims. ### **Monthly rental and reasonable useful lifetime** Bill K0738 monthly within the 36-month oxygen equipment rental period. The reasonable useful lifetime is five years beginning on the initial date of service, and months 37–60 require the supplier that billed the thirty-sixth month to continue furnishing equipment, accessories, contents if applicable, maintenance, and repairs without additional rental payments. ### **Mutually exclusive from E0431** Do not bill E0431 in the same rental period as K0738. K0738 covers the home transfill feature for gaseous systems, so separate rental of a portable gaseous oxygen system is not payable when K0738 is on the claim. ### **Modifier use tied to coverage group and flow rate** For initial claims or new 36-month rental periods starting on or after April 1, 2023, append N1, N2, or N3 to indicate Group I, Group II, or Group III criteria met. For documented flow rates greater than 4 LPM where portable oxygen is prescribed, use QF or QB as applicable with the corresponding stationary and portable oxygen codes. Use QA or QE for flow rates less than 1 LPM when criteria are met. ### **Contents billing interactions** Understand when portable or stationary contents are separately payable. Contents are included when stationary equipment is being paid. If the stationary rental ends and the patient uses gaseous or liquid systems, portable and/or stationary contents may begin according to policy. Deliver up to three months at once, but bill one unit of service per month for stationary and one for portable as applicable. ### **Replacement equipment and the RA modifier** When equipment is replaced due to end of reasonable useful lifetime, damage beyond repair, theft, or loss, submit the initial rental month for the replacement equipment with the RA modifier and include a narrative explaining the reason. Routine malfunction, wear, or repair does not start a new 36-month period. ### **Break-in-service and relocation considerations** If there is a break-in-need longer than 60 days plus the remainder of the month during months 1–36 and new medical necessity is established, a new rental cycle may begin. During months 37–60, a new cycle does not start. When a patient relocates, the home supplier must continue service or arrange with another supplier; only one supplier may bill in a rental month.

## **K0738 applicable modifiers** Use the following modifiers with K0738 when criteria are met. - **N1, N2, N3**: indicate that Group I, II, or III coverage criteria are fully met for initial claims or new rental periods starting April 1, 2023 or later. - **QA, QE**: document flow rates less than 1 LPM, either averaged per rule or “at rest” as specified. - **QB, QF**: document flow greater than 4 LPM with portable oxygen prescribed; use with both stationary and applicable portable oxygen codes. - **QG, QR**: document greater than 4 LPM per “at rest” or averaged day–night flow rules when portable is or is not prescribed as defined in policy. - **GA, GZ, GY**: report expectation of medical necessity denial with or without a valid ABN, or statutory exclusion. - **RA**: append on the first month only when submitting claims for replacement equipment due to end of useful life or specific incident.

## **Other relevant codes** The following codes are commonly used alongside or in relation to K0738 and help clarify coverage, modality, and content billing interactions. - **E1390** – oxygen concentrator, stationary rental. - **E0431** – portable gaseous oxygen system, rental; cannot be billed with K0738 in the same period. - **E1392** – portable oxygen concentrator, rental; a standalone device that includes an integrated battery or replaceable batteries and a battery charger. - **E0433** – portable liquid oxygen system via home liquefier; if billed, do not bill E0434. - **E0434** – portable liquid oxygen system, rental; mutually exclusive with E0433 for the same period. - **E0443** – portable gaseous oxygen contents; payable when content rules allow after rental transitions.