Emergency Triage, Treat, and Transport (ET3) Model

The ET3 Model ended early on December 31, 2023, two years prior to the performance period end date. This decision was made due to lower than expected participation and lower than projected interventions. Emergency Medical Services remain an area of focus for CMS, and we believe that the lessons learned from the ET3 Model can aid in the development of potential future initiatives. This decision does not affect Model Participants’ participation in the Model through December 31, 2023.


Emergency Triage, Treat, and Transport (ET3) was a voluntary, five-year payment model that provided greater flexibility to ambulance care teams to address emergency health care needs of Medicare Fee-for-Service (FFS) beneficiaries following a 911 call. CMS continued to pay to transport a Medicare FFS beneficiary to a hospital emergency department or other covered destination. In addition, under the model, CMS paid participants to 1) transport to an alternative destination partner, such as a primary care office, urgent care clinic, or a community mental health center (CMHC), or 2) initiate and facilitate treatment in place with a qualified health care partner, either at the scene of the 911 emergency response or via telehealth.

The model allowed beneficiaries to access the most appropriate emergency services at the right time and place. As a result, the ET3 Model aimed to improve quality and lower costs by reducing avoidable transports to the ED and unnecessary hospitalizations following those transports.


  • When a person experiencing a medical issue called 911, the responding ambulance team often would take the person straight to the emergency department, even if they did not need emergency medical treatment at a hospital. When this happened, patients might incur higher out-of-pocket costs, and they may have also taken up limited hospital bed space, resulting in longer wait times for other patients in need of critical care.
  • The Emergency Triage, Treat, and Transport (ET3) Model enabled ambulance teams to offer a person in need of less serious medical attention other options. These options included transportation to another medical facility to get care, such as an urgent care center, medical clinic or behavioral health center, depending on the person’s needs, or treatment with a qualified healthcare provider right where they were (in person or by telehealth). If a person was offered one of these options under the model, they could still ask the ambulance team to take them to the hospital. 
  • Treating people in non-emergency room settings may have saved them and their families time waiting in the emergency department and care may have been provided more quickly, hospital costs may have been avoided when appropriate, and ambulance teams may have focused on taking patients with the greatest emergency needs to the hospital.


Medicare regulations have historically only allowed payment for emergency ground ambulance services when individuals are transported to hospitals, critical access hospitals, skilled nursing facilities, and dialysis centers. Most beneficiaries who call 911 with a medical emergency are therefore transported to one of these facilities, and most often to a hospital ED, even when a lower-acuity destination may more appropriately meet an individual’s needs.

In March 2020, CMS announced in a press release an Interim Final Rule with Comment Period (IFC) that provides temporary regulatory waivers and new rules to equip the American healthcare system with maximum flexibility to respond to the COVID-19 Public Health Emergency (PHE). The IFC and all of CMS’s COVID-19 waivers and flexibilities can be found on the CMS Coronavirus waivers & flexibilities web page.

For the duration of the Coronavirus-19 disease Public Health Emergency, CMS temporarily expanded the list of allowable destinations for ambulance transports. Participants in the model will be able to continue to access these flexibilities while participating in the model, for as long as they are available.

As part of an ET3 intervention, Participants in the ET3 Model received payment for ambulance services for transport to alternative destinations at the appropriate emergency Basic Life Support (BLS-E) or emergency Advance Life Support, Level 1 (ALS1-E) rate. When implementing the ET3 transport to an alternative destination intervention, the Participant must have established arrangements with alternative destination partners located within their model region and complied with all related ET3 Model requirements.

Participants may have also transported beneficiaries to covered destinations under the ambulance flexibilities and bill Medicare as usual. These transports would not be considered ET3 interventions, although, in many cases, they would have sufficed to allow ET3 Participants to also implement the optional Treatment in Place intervention, which Participants may have only implemented if they were also making transport to alternative destinations available to ET3 Model beneficiaries. Payment rates for transport under the flexibilities and under the ET3 Model were the same.

Model Details

With the support of local governments, their designees, or other entities that operate or have authority over one or more 911 dispatches, ambulance suppliers and providers triaged people seeking emergency care based on their presenting needs. The model aimed to ensure Medicare FFS beneficiaries received the most appropriate care, at the right time, and in the right place. The model may have helped make EMS systems more efficient and provided beneficiaries broader access to the care they needed. Beneficiaries who received treatment from alternative destinations may also have saved on out-of-pocket costs. An individual could always choose to be brought to an ED if he/she preferred.

The ET3 Model aimed to reduce expenditures and preserve or enhance quality of care by:

  • Providing person-centered care, such that beneficiaries received the appropriate level of care delivered safely at the right time and place while having greater control of their healthcare through the availability of more options
  • Encouraging appropriate utilization of services to meet health care needs effectively.
  • Increasing efficiency in the EMS system to more readily respond to and focus on high-acuity cases, such as heart attacks and strokes.


The Participants of the ET3 Model were Medicare-enrolled ambulance service suppliers and hospital-owned ambulance providers. Upon arriving on the scene of a 911 response, participating ambulance suppliers and providers may have triaged Medicare FFS beneficiaries to one of the model’s interventions. As part of a multi-payer alignment strategy, the Innovation Center encouraged ET3 Model participants to partner with additional payers, including state Medicaid agencies, to provide similar interventions to all people in their geographic areas.

As of December 30, 2023, there were 147 ambulance suppliers and providers participating in the Emergency Triage, Treat, and Transport (ET3) Model. Data available in the Chronic Conditions Warehouse (CCW) as of February 26, 2024, reflected the following information related to the ET3 Model for paid Medicare Fee-for-Service (FFS) claims. This data reflected dates of service between January 1, 2021, and December 31, 2023:

  • Total number of participants who have billed for ET3 Model Interventions: 72
  • Number of unique beneficiaries who have received ET3 Model Interventions (cumulative of Transport to Alternate Destinations [TAD] and Treatment in Place [TIP]): 2,964
  • Total number of ET3 Interventions (cumulative of TAD and TIP): 3,397
  • Total number of TIP interventions: 3,144
  • Total number of TAD interventions: 253

Note/Footnote: All ET3 Intervention claims counts are based on data in the CCW, identified by a National Provider Identifier (NPI) corresponding with an ET3 Model Participant. All claims include Healthcare Common Procedure Coding System (HCPCS) billing codes A0427 or A0429. For TIP interventions, claims must include a Participant NPI; and destination modifier ending in "W"; and HCPCS code A0427 or A0429; and no other claim lines (including A0425). For TAD Interventions, the claim must include a Participant NPI; and applicable destination modifier; and HCPCS code A0429 or A0427; and HCPCS code A0425; and no other claim lines. A unique beneficiary may receive more than one ET3 Intervention during the model period of performance. However, a beneficiary may only receive one ET3 Intervention during an encounter. Medicare claims may be filed up to 12 months, or 1 calendar year after the date of service.


The Innovation Center released a Request For Applications (RFA) (PDF) in Summer 2019 to solicit Medicare-enrolled ambulance suppliers and providers. The ET3 Model opened the RFA Online Portal from August 5, 2019 through October 5, 2019 and announced the selection of 205 applicants on February 27, 2020. The Innovation Center issued a Notice of Funding Opportunity (NOFO) on March 12, 2021 for up to 40 cooperative agreements, however on September 13, 2021, the CMS announced its decision to withdraw the ET3 NOFO due to insufficient applications received. CMS considered its options carefully before reaching the decision to not implement the medical triage line component of the Model. The insufficient number of applications received would not allow for a sufficient number of Agreements to adequately determine whether the medical triage line intervention described in the NOFO has the potential to maintain or improve quality of care for beneficiaries and reduce Medicare program spending under the Model.


The ET3 Model RFA ambulance component had a five-year performance period. In response to the COVID-19 PHE, CMS delayed the start of the ET3 Model. The first performance period for ET3 Model Participants began on January 1, 2021. 


Request for Applications (RFA)

Additional Information


If you are interested in additional information or have questions about the ET3 Model, please review the Frequently Asked Questions page or contact ET3model@cms.hhs.gov.

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