Published 03/20/2024

Ambulance Suppliers cannot issue an ABN for any emergency transport and cannot shift liability to the beneficiary under the Limitation On Liability (LOL) Provision. See the Social Security Act §1862(a)(1) for more detailed information on LOL. 

Resource: CMS Internet-Only Manual (IOM) Pub. 100-04, Claims Processing Manual (PDF), Chapter 30 — Financial Liability Protections.

Last Reviewed: 3/20/2024

No. Transport to a physician’s office is covered only under the following circumstance:

  • The ambulance transport is enroute to a Medicare covered destination as described in the CMS Internet-Only Manual (IOM) Pub. 100-02, Medicare Benefit Policy Manual (PDF), Chapter 10, §10.3
  • During the transport, the ambulance stops at a physician's office because of the patient's dire need for professional attention; immediately thereafter, the ambulance continues to the covered destination
  • In such cases, the patient will be deemed to have been transported directly to a covered destination and payment may be made for a single transport and the entire mileage of the transport, including any additional mileage traveled because of the stop at the physician’s office

Note: See COVID-19: Expanded Use of Ambulance Origin/Destination Modifiers and Ambulances: CMS Flexibilities to Fight COVID-19 (PDF) for exceptions that existed during the COVID-19 Public Health Emergency.

Resource: CMS Internet-Only Manual (IOM) Pub. 100-02, Medicare Benefit Policy Manual (PDF), Chapter 10, §10.3.8 — Ambulance Service to Physician’s Office.

Last Reviewed: 3/20/2024

Emergency Response
Definition: Emergency response is a BLS or ALS1 level of service that has been provided in immediate response to a 911 call or the equivalent. An immediate response is one in which the ambulance provider/supplier begins as quickly as possible to take the steps necessary to respond to the call.

  • The phrase "911 call or equivalent" is intended to establish the standard that the nature of the call at the time of dispatch is the determining factor. Regardless of the medium by which the call is made (e.g., a radio call could be appropriate), the call is of an emergent nature when based on the information available to the dispatcher at the time of the call. It is reasonable for the dispatcher to issue an emergency dispatch in light of accepted, standard dispatch protocol.
  • An emergency call need not come through 911 even in areas where a 911 call system exists. However, the determination to respond emergently must be in accord with the local 911 or equivalent service dispatch protocol. 
  • If the call came in directly to the ambulance provider/supplier, then the provider’s/supplier’s dispatch protocol and the dispatcher’s actions must meet, at a minimum, the standards of the dispatch protocol of the local 911 or equivalent service
  • In areas that do not have a local 911 or equivalent service, then both the protocol and the dispatcher’s actions must meet, at minimum, the standards of the dispatch protocol in another similar jurisdiction within the state. If there is no similar jurisdiction, then the standards of any other dispatch protocol within the state must be met. Where the dispatch was inconsistent with this standard of protocol, including where no protocol was used, the beneficiary’s condition (e.g., symptoms) at the scene determines the appropriate level of payment. 

Resource: CMS Internet-Only Manual (IOM) Pub. 100-02, Medicare Benefit Policy Manual (PDF), Chapter 10, Section 30.1.1 — Ground Ambulance Services.

Last Reviewed: 3/20/2024

Multiple patient transports must be submitted with HCPCS modifier GM on the appropriate ambulance base code and mileage code. 

  • Submit the appropriate origin and destination modifiers in the first modifier position and HCPCS Modifier GM in the second modifier position

Documentation required with claims for multiple patient transports:

  • The number of patients transported
  • The Medicare numbers for each Medicare beneficiary in the vehicle at the same time. If there was no other Medicare beneficiary in the vehicle, this must be clearly documented.
  • The total mileage traveled for that individual Medicare beneficiary
  • This information must be in the appropriate documentation record for EDI claims and as an attachment to the CMS-1500 claim form
  • Claims submitted without this information will be rejected as unprocessable and must be resubmitted as new claims


Last Reviewed: 3/20/2024

No. Level of transport is based on the level of care provided (i.e., procedure), not merely the personnel involved in administering the care.

Advanced Life Support Intervention

  • Definition: An ALS intervention is a procedure that is in accordance with state and local laws. It is required to be done by an EMT-Intermediate or an EMT-Paramedic.
  • Application: An ALS intervention must be medically necessary to qualify as an intervention for payment for an ALS level of service. An ALS intervention applies only to ground transports.

Resource: CMS Internet-Only Manual (IOM) Pub. 100-02, Medicare Benefit Policy Manual (PDF) Chapter 10, Section 30.1.1 — Ground Ambulance Services.

Last Reviewed: 3/20/2024

This depends on how the facility is licensed. If it is licensed as a physician’s office, then the appropriate HCPCS modifier would be P. If it is licensed as a hospital, then you would use HCPCS modifier H. If the facility is licensed as neither a physician’s office nor a hospital, then HCPCS modifier D (Diagnostic or therapeutic site other than P or H) would be appropriate. You will need to verify this with the wound care center.

Please Note: HCPCS modifier D would also be appropriate for an independent diagnostic testing facility, cancer treatment center or radiation therapy center. 

Resource: CMS Internet-Only Manual (IOM) Pub. 100-04, Medicare Claims Processing Manual (PDF), Chapter 15, section 30.2.2 — SNF Billing.

Last Reviewed: 3/20/2024

There is no specific modifier designated for hospice. You would use the appropriate HCPCS modifier based on the location of where the patient is receiving the service. The most common HCPCS modifiers for hospice providers would be:

  • H (hospital)
  • E (residential, domiciliary, custodial facility)
  • N (skilled nursing facility)

Please keep in mind that all other coverage requirements must be satisfied. For instance, a transport from "R" (residence) to "E" (residential, domiciliary, custodial facility) would not be covered because it is essentially a transport between two residences.

If it is determined that the claim should be submitted to Medicare Part B, please consider adding HCPCS modifier GW (service not related to the hospice patient’s terminal condition) to your claim.

Resource: CMS Internet-Only Manual (IOM) Pub. 100-04, Medicare Claims Processing Manual (PDF), Chapter 15 — Ambulance, Section 30.A.

Last Reviewed: 3/20/2024

The CO-97 denial is "Patient was an inpatient on the date of service." Some hospital facilities do not understand why we bill them for our transports in order for us to get paid for our services.

Yes, the transport is not billable to Part B if the patient’s status is inpatient for both origin and destination with no discharge in between. For instance, intra-campus transfers and "patient transportation" for specialized care where the patient maintains inpatient status with the original provider are both billable to Part A, not Part B. The hospital would then pay the ambulance supplier.

Resource: CMS Internet-Only Manual (IOM) Pub. 100-02, Medicare Benefit Policy Manual (PDF), Chapter 10, Section 10.3.3.

Last Reviewed: 3/20/2024

After doing the advanced life support (ALS) assessment, if the patient is in need of ambulance transport without any other ALS services being performed, then this transport would be payable at the ALS1 rate. However, if after the ALS assessment is performed, there is no medical necessity for transport then no Medicare benefit exists. Accordingly, Medicare would not be liable for any payments.

Resource: CMS Internet-Only Manual (IOM) Pub. 100-02, Medicare Benefit Policy Manual (PDF), Chapter 10 — Ambulance, section 30.1.1.

Last Reviewed: 3/20/2024


Question 1. What does RSNAT PA stand for?
Answer: Repetitive, Scheduled Non-Emergent Ambulance Transport (RSNAT) Prior Authorization (PA). RSNAT transports are defined as medically necessary ambulance transports that occur three times or more during a 10-day period or at least once per week for three weeks or longer.

Question 2. When did the RSNAT PA model begin?
Answer: The RSNAT PA model began in the states of New Jersey, Pennsylvania and South Carolina on December 1, 2014. The model was expanded nationwide to all states by August 2022. 

The RRB SMAC implemented the Repetitive Scheduled Non-emergent Ambulance Transport (RSNAT) Prior Authorization (PA) model on July 18, 2022, for Railroad Medicare beneficiaries nationwide for transports on and after August 1, 2022.

Question 3. What is the purpose of the RSNAT PA model?
Answer: CMS began operating the RSNAT PA model to test whether PA of RSNAT services covered under Medicare Part B would lower program spending, while maintaining or improving quality patient care. It is designed to ensure that all relevant coverage, coding and medical record(s) requirements are met before the service is rendered to patients and before claims are submitted for payment. Therefore, this model can assist in reducing appeals for claims that may otherwise be denied.

Question 4. Which HCPCS codes are included in the PA RSNAT Model?
Answer: The following ambulance HCPCS codes are subject to prior authorization: 

  • A0426: Ambulance service, Advanced Life Support (ALS), non-emergency transport, Level 1 
  • A0428: Ambulance service, Basic Life Support (BLS), non-emergency transport

HCPCS code A0425 is considered an associated service and will not receive prior authorization.

Question 5. How many trips can we receive prior authorization for if we participate in the PA RSNAT model?
Answer: By submitting a complete cover sheet and required documentation, a supplier can receive provisional prior authorization for as many as 40 round trips or 80 one-way transports in a 60-day period. For scheduled trips beyond the PA number, a second PA request is required.

Question 6. Am I required to submit additional documentation to receive prior authorization for my ambulance claims?
Answer: Prior authorization does not create new clinical documentation requirements. Instead, it requires the same information that is already required to support Medicare payment, just earlier in the process. This includes, but is not limited to, a signed and valid Physician Certification Statement (PCS) and current documentation from the patient’s medical record to support medical necessity of RSNAT PA services.

Question 7. Are ambulance suppliers required to participate in the PA RSNAT Model?
Answer: Prior authorization for repetitive, scheduled non-emergent ambulance transports is voluntary. However, if suppliers do not submit a prior authorization request for a beneficiary before their fourth-round trip within a 30-day period, their claims related to repetitive, scheduled non-emergent ambulance transports will be subject to prepayment medical review.

Participation in this model is recommended. Prior authorization helps ambulance suppliers ensure that their services comply with applicable Medicare coverage, coding and payment rules before services are rendered and before claims are submitted for payment. This model allows providers and suppliers the opportunity to address issues with claims prior to rendering services and submitting claims for payment, which has the potential to reduce appeals for claims that may otherwise be denied. Ambulance suppliers are encouraged to submit prior authorization request prior to the beneficiary’s fourth trip in a 30-day period. 

Question 8. How can we submit a RSNAT PA request to Railroad Medicare?
Answer: Requests may be submitted via mail or fax, through the Palmetto GBA eServices portal, or through the Electronic Submission of Medical Documentation (esMD) system. Please see our Requesting Prior Authorization for Repetitive, Scheduled Non-Emergent Ambulance Transports article for more information.

Question 9. How long will it take for suppliers to receive a decision response for a prior authorization request? 
Answer: MACs will make every effort to postmark a decision on a prior authorization request within ten business days for both initial and resubmitted requests.

Question 10. Will we receive a tracking number for each prior authorization decision? 
Answer: Yes. Each completed prior authorization request is assigned a 14-byte unique tracking number (UTN). This number is included on the decision letter and will be used when submitting claims. A non-affirmed UTN will also be used when you send a resubmission for a non-affirmed PA request. 

Question 11. How many trips are allowed under a single prior authorization request?
Answer: A provisional affirmative prior authorization decision affirms a specified number of trips within a specific amount of time and can be for all or part of a requested number of trips. The prior authorization decision, justified by the beneficiary’s condition, may affirm up to 40 round trips (which equates to 80 one-way trips) per prior authorization request in a 60-day period. Transports exceeding 40 round trips (or 80 one-way trips) in a 60-day period will require an additional prior authorization request. 

MACs may consider an extended affirmation period for beneficiaries with a chronic medical condition that is deemed not likely to improve over time. The prior authorization decision, justified by the beneficiary’s chronic medical condition, may affirm up to 120 round trips (which equates to 240 one-way trips) per prior authorization request in a 180-day period. Ambulance suppliers are still responsible for maintaining a valid PCS at all times.

Question 12. Where can I find additional information on the RSNAT Prior Authorization Model?
Answer: You can find additional information on our Ambulance Prior Authorization page and in the following CMS resources: 

  • CMS Prior Authorization of Repetitive, Scheduled Non-Emergent Ambulance Transport (RSNAT) web page
  • CMS Repetitive, Scheduled Non-Emergent Ambulance Transport Prior Authorization Model Operational Guide (PDF)
  • CMS Repetitive, Scheduled Non-Emergent Ambulance Transport (RSNAT) Prior Authorization Model Frequently Asked Questions (PDF)

Last Reviewed: 3/20/2024

If the beneficiary/representative refuses to authorize the submission of a claim, including a refusal to furnish an authorizing signature, then the ambulance provider/supplier may not bill Medicare. The ambulance provider may bill the beneficiary (or his or her estate) for the full charge of the ambulance items and services furnished. If, after seeing this bill, the beneficiary/representative decides to have Medicare pay for these items and services, then a beneficiary/representative signature is required. The ambulance provider/supplier must afford the beneficiary/representative this option within the claims filing period.

Reference: CMS Internet-Only Manual (IOM) Pub. 100-02, Medicare Benefit Policy Manual (PDF), Chapter 10, Section 20.1.2.

Last Reviewed: 3/20/2024

Physician Certification Statements (PCS) are required for patients that are under the direct care of a physician. They are required for scheduled and non-scheduled non-emergency ambulance transports. A PCS from the patient’s attending physician can assist in supporting medical necessity. However, the presence of the signed PCS does not, by itself, determine medical necessity. All other coverage criteria must also be met.

A PCS is not required for emergency transports or for non-scheduled, non-emergency transports of patients residing at home or a facility where they are not under the direct care of a physician.

Resource: 42 CFR §410.40 Coverage of Ambulance Services.

Last Reviewed: 3/20/2024

Medicare requires the signature of the beneficiary, or that of his or her representative, for both the purpose of accepting assignment and submitting a claim to Medicare. If the beneficiary is unable to sign because of death or a mental or physical condition, there are other recourses that can be followed. See the complete list in the Railroad Medicare article, Beneficiary Signature Requirements.


Last Reviewed: 3/20/2024

When a patient needs more care than is available at the hospital of origin, Medicare may cover the cost of the transport to a more appropriate facility. If the transport is medically necessary, the base rate would be covered. The Medicare allowance for mileage is the mileage to the nearest facility capable of providing the medically required services. If the patient is transported beyond the closest capable facility, the remainder of the mileage will deny as not medically necessary.

Ambulance transports between facilities are a covered Medicare benefit when other means of transport cannot be used and when the required services are not available at the originating hospital/facility. "Required services" means that the institution is generally equipped to provide the needed care for the illness or injury involved. The fact that a more distant institution is better equipped, either qualitatively or quantitatively, to care for the patient does not warrant a finding that a closer institution does not have the "required services." A finding is warranted if beneficiary’s condition required a higher level of trauma care or other specialized service that was only available at a more distant hospital. An institution is also not considered an appropriate facility if there is no bed available. However, Medicare will presume that beds were available at the local institution unless evidence is presented that beds were not available at the originating facility at the time the ambulance service was rendered. Please see CMS Internet-Only Manual (IOM) Pub. 100-02, Medicare Benefit Policy Manual (PDF), Chapter 10, Section 10.3.6, for more information.

Last Reviewed: 3/20/2024

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