CPT code 33946: ECMO initiation, venovenous, age six and older2026 Medicare rate & RVUs

Medicare pays $279.57 for 33946 nationally in a facility.

Medicare allowed amount for participating (non-QP) physicians, before deductible, coinsurance and claim adjustments. Not a patient’s bill or a hospital charge.

What 33946 covers

This service covers starting venovenous extracorporeal membrane oxygenation or extracorporeal life support in a patient age six or older. Venous blood is routed through an extracorporeal circuit for gas exchange and returned to the venous circulation, supporting patients with severe respiratory failure when conventional respiratory support is inadequate. The physician directing initiation may be a critical care specialist, cardiothoracic surgeon, or another clinician experienced in ECMO, typically in an intensive care setting.

Report 33946 for the initiation phase, not for ongoing daily ECMO management or an arterial-return configuration. The record should establish the patient’s age, the venovenous support configuration, the clinical need for ECMO, and the physician’s work initiating the service. Cannula insertion has separate codes in the ECMO/ECLS code family when that work is performed.

This summary was written with AI assistance from CMS physician fee schedule data and checked against the CMS billing rules shown here. Rates on this page come directly from CMS files.

Where 33946 pays more and less

The same RVUs, adjusted for each area’s costs. Open a locality for its calculation, history and nearby areas.

109 of 109 payment localities

33946 rates by state

Office rate range in each state. Select a state to see its payment localities.

How the 33946 rate is calculated

Each of 33946’s three RVUs is multiplied by a geographic index (GPCI) for the payment locality, added up, and multiplied by the conversion factor. Drag the indexes or enter a ZIP to see what moves the rate.

Payment rules and modifiers for 33946

33946 has no global surgery period, no multiple-procedure, bilateral or assistant-at-surgery adjustment, and no professional/technical split. What changes the payment is where the service happens: the place of service on the claim decides whether Medicare pays the office or the facility rate.

33946 compared with similar codes

How to choose

33947ECMO initiationVenoarterial configuration

Both codes report ECMO/ECLS initiation in patients age six and older. Choose 33946 for venovenous support and 33947 for venoarterial support.

33948ECMO managementVenovenous support

This code reports daily management of venovenous ECMO/ECLS after initiation; 33946 reports starting the support.

33949ECMO managementVenoarterial support

This code reports daily management of venoarterial ECMO/ECLS, rather than venovenous initiation.

33951ECMO cannulationPercutaneous, age 5 or older

This code represents peripheral cannula insertion, not initiation of the venovenous ECMO/ECLS service.

Codes related to 33946

Related codes aren’t interchangeable: bill the code that matches the service performed.

Where these rates come from

FeeBase calculates base physician payments from CMS work, practice-expense and malpractice RVUs, adjusted by each locality’s geographic indexes and the conversion factor. Services without a published rate are labeled, never given a made-up amount. Amounts are Medicare allowed amounts before claim adjustments: not a patient’s bill or a commercial rate.

CMS RVU26D · effective Oct 1, 2026 through the day before Jan 1, 2027

Open CMS sourceHow we calculate rates