Ambulance Modifiers & Codes | How To Bill Ambulance Services (2022)

Below you can find the origin and destination codes for ambulance modifiers and the HCPCS codes for reporting ambulance services.

1. How Are Ambulance Modifiers Used?

Ambulance service claims must be reported with origin and destination codes provided by HCPCS. Two alpha characters create these codes and can be reported as ambulance modifiers.

The alpha characters (except X) represent destination and origin codes. This code must be reported in the modifier field for ambulance service claims.

The origin of an ambulance trip can be reported with the first position, and the second alpha code can be used for the trip’s destination.

2. Origin & Destination Codes For Ambulance Modifiers

Below you can find the list of valid alpha codes used in the modifier field for ambulance service claims according to Medicare and CMS.

X: Intermediate stop at physician’s office on the way to the hospital. Report X as a destination code only.
S: Scene of accident or acute event.
R: Residence.
P: Physician’s office.
N: Skilled nursing facility.
J: Freestanding ESRD facility.
I: Site of transfer between modes of ambulance transport. For example, an airport or helicopter pad.
H: Hospital.
G: Hospital-based ESRD facility.
E: Custodial facility domiciliary, residential.
D: Therapeutic or diagnostic site. This needs to be another site than P or H when used as origin codes.

3. Ambulance Coding Guidelines

It is possible that HCPCS modifiers are similar or the same as the ambulance modifiers reported with the ambulance transportation codes. The modifiers can only specify the destination and origin of the ambulance.

The characters below on ET3 model ambulance claims stipulate;

that the beneficiary is treated in place and, therefore, no transportation was needed; or
an allowable alternative destination.

According to CMS, you can use the characters below as a destination modifier since the ET3 model was introduced on the 1st of January 2021. They can only be billed with ET3 Model ambulance claims and not as an origin code for an ambulance modifier.

W: Treatment in place (telehealth or in person).
U: Urgent care facility.
O: Physician’s office.
F: Federally qualified health center.
C: Community mental health center.

4. Ambulance Codes

Services provided during an ambulance trip can be billed with the HCPCS codes below.

4.1 What Is HCPCS Code A0422?

HCPCS A0422 covers oxygen and its supply during a life-sustaining situation for a patient with advanced or basic life support during an ambulance trip.

4.1.1 Description

The HCPCS book describes A0422: “Ambulance (ALS or BLS) oxygen and oxygen supplies, life-sustaining situation.”

4.1.2 Billing Guidelines

HCPCS A0422 can only be used once during an ambulance trip. It covers all the oxygen the emergency staff supplies to the patient in the ambulance during a basic or advanced life situation.

Medicare does not cover HCPCS code A0422.

4.2 What Is HCPCS Code A0424?

HCPCS code A0424 covers an extra ambulance attendant during ambulance transport for escorting a patient receiving advanced or basic life support on the ground or in the air.

4.2.1 Description

The HCPCS book describes A0424 as: “Extra ambulance attendant, ground (ALS or BLS) or air (fixed or rotary winged); (requires medical review).”

4.2.2 Billing Guidelines

Medicare does not cover HCPCS code A0424. However, other third-party payers might cover this service. Check the guidelines for reporting A0424 for the required documentation.

4.3 What Is HCPCS Code A0425?

HCPCS A0425 covers the ground mileage per mile during an ambulance trip with a patient.

4.3.1 Description

The HCPCS book describes A0425 as: “Ground mileage, per statute mile.”

4.3.2 Billing Guidelines

Be aware that providers report mileage in fractional units for hard-copy claim submissions. Therefore, you can round up the total miles to the closest tenth of a mile when you report HCPCS code A0425.

On the other hand, electronic submissions need to be rounded to the nearest whole mile when you report HCPCS code A0425.

Reporting requirements for A0425 might differ per payer. Check their requirements before billing this code.

4.4 What Is HCPCS Code A0426?

HCPCS A0426 covers a patient transported with non-emergency transport and advanced life support.

A0426 can also be billed for the provision level of one prehospital service (for example, ALS assessment) or a minimum of one ALS intervention provided by the ambulance staff.

4.4.1 Description

The HCPCS book defines HCPCS code A0426 as: “Ambulance service, advanced life support, non-emergency transport, level 1 (ALS 1).”

4.4.2 Billing Guidelines

Medicare covers nonemergency ambulance transportation as described by HCPCS A0426 if the transport is medically necessary due to the patient’s condition. For example, a bed-confided patient.

Medicare does not cover A0426 if the service could have also been provided to the patient at the point of origin. The patient’s home is an example that won’t be covered.

4.5 What Is HCPCS Code A0427?

HCPCS A0427 covers emergency transportation of a patient with ALS (advanced life support) in an ambulance, emergency prehospital services, and at least one intervention by the ambulance staff.

4.5.1 Description

The HCPCS book describes A0427 as: “Ambulance service, advanced life support, emergency transport level 1 (ALS 1-emergency)Ambulance service, advanced life support, emergency transport, level 1 (ALS 1-emergency).”

4.6 What Is HCPCS Code A0428?

HCPCS A0428 covers non-emergency transport in an ambulance with BLS (basic life support) and interventions or assessments provided by the ambulance staff.

4.6.1 Description

The HCPCS book describes A0428 as follows: “Ambulance service, basic life support, non-emergency transport, (BLS).”

4.6.2 Billing Guidelines

Medicare only covers HCPCS code A0428 if the patient needs a service that cannot be provided at the ambulance’s point of origin (for example, at a patient’s home).

4.7 What Is HCPCS Code A0429?

HCPCS A0429 can be used for a patient who received basic life support (BLS) during an emergency transport in an ambulance. Interventions and assessments provided by the ambulance staff are also included.

4.7.1 Description

The HCPCS book describes A0429 as: “Ambulance service, basic life support, emergency transport (BLS-emergency).”

4.8 What Is HCPCS Code A0430?

HCPCS A0430 covers on-way transportation with a conventional fixed-wing air ambulance. The air ambulance is often used for patients that need immediate medical care or if ground transport can be a risk to the patient’s health.

4.8.1 Description

The HCPCS book describes A0430 as follows: “Ambulance service, conventional air services, transport, one way (fixed wing).”

4.9 What Is HCPCS Code A0431?

HCPCS A0431 covers the transport of a patient by rotary wing air ambulance transport (helicopter) to carry them to a (medical) facility.

4.9.1 Description

The HCPCS book describes A0431 as follows: “Ambulance service, conventional air services, transport, one way (a rotary wing).”

4.9.2 Billing Guidelines

HCPCS code A0431 is usually only covered for the amount it would cost to bring the medical care services to the patient.

Destination facilities can include;

dialysis facilities;
skilled nursing facilities;
critical access hospitals; and
hospitals.

Individual state Medicaid programs may provide non-emergency transportation services.

The reimbursement for A0431 for a Medicare patient includes carrier judgment.

4.10 What Is HCPCS Code A0432?

HCPCS A0432 covers life-saving ALS services (Advanced Life Support) provided in a rural area during a medical emergency. Ambulance transportation is not included if provided by a local volunteer service.

4.10.1 Description

The HCPCS book describes A0432 as follows: “Paramedic intercept (PI), rural area, transport furnished by a volunteer ambulance company which is prohibited by state law from billing third-party payers.”

4.10.2 Billing Guidelines

Reimbursement of A0432 includes carrier judgment for medicare patients.

Paramedic intercept services and ambulance transport are paid separately by Medicare if A0432 is performed in a rural area and under contract with an ambulance service provided by local volunteers.

State laws often forbid billing for the ambulance service provided by local volunteers. The ambulance service provided during the A0432 service needs to meet the program’s certification requirements and can only provide BSL services and transportation.

The provider needs to be ALS certified and bill all other recipients for the ALS service, including Medicare beneficiaries.

4.11 What Is HCPCS Code A0433?

HCPCS A0433 covers the transportation of patients with a ground ambulance and includes emergency prehospital services that use invasive medical actions.

Examples of emergency prehospital services that use invasive medical actions are;

defibrillation;
cardioversion;
intubation; and
administration of advanced life support interventions.

The necessary supplies and services for the invasive medical actions are included in A0433.

4.11.1 Description

The HCPCS book describes A0433 as follows: “Advanced life support, level 2 (ALS 2).”

4.11.2 Billing Guidelines

Reimbursement for HCPCS code A0433 includes carrier judgment for Medicare patients.

4.12 What Is HCPCS Code A0434?

HCPCS A0434 covers inter-facility transportation of a critically injured or ill patient with a ground ambulance. The services and supplies provided during the transport are included in A0434.