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Ambulance Modifiers

Modifiers identifying place of origin and destination of the ambulance trip must be submitted on all ambulance claims. The modifier is to be placed next to the Health Care Procedure Coding System (HCPCS) code billed. For more information regarding valid ambulance procedure codes, please refer to the Ambulance Procedure Codes article.

Each of the modifiers may be utilized to make up the first and/or second half of a twoletter modifier. The first letter must describe the origin of the transport, and the second letter must describe the destination (Example: if a patient is picked up at his/her home and transported to the hospital, the modifier to describe the origin and destination would be RH).

Incorrect use of modifiers could result in longer processing time and/or denial of services.

The following is a list of the only valid modifiers to be used by ambulance suppliers:

Code Description
D Diagnostic or therapeutic site other than "P" or "H"
E Residential, domiciliary, custodial facility, nursing home other than SNF (other than 1819 facility)
G Hospital based dialysis facility (hospital or hospital-related) which includes:
- Hospital administered/Hospital located
- Non-Hospital administered/Hospital located
H Hospital
I Site of transfer (e.g., airport, ferry, or helicopter pad) between modes of ambulance transport
J Non-hospital-based dialysis facility
- Non-Hospital administered/Non-Hospital located
- Hospital administered/Non-Hospital located
N Skilled Nursing Facility (SNF) (1819 Facility)
P Physician's Office (includes HMO non-hospital facility, clinic, etc.)
R Residence
S Scene of Accident or Acute Event
X Destination Code Only) Intermediate stop at physician's office en route to the hospital (includes HMO non-hospital facility, clinic, etc.)

Additional modifiers for ambulance services:

GY Use when billing for a statutorily excluded services. Example - Patient transport is for a non-covered condition that does not meet the definition of any Medicare benefit. The provider is expecting a denial.

Refer to Modifier Fact Sheet for GY Modifier for additional information
QL Use when the patient is pronounced deceased after the ambulance is called. The patient is pronounced dead after the ambulance is called but before transport. Ground providers can bill a BLS service along with the QL modifier.

See CMS Internet Only Manual, 100-2, Medicare Benefits Policy Manual, Chapter 10, Section 10.2.6.

Air providers can use the appropriate air base rate code (fixed wing or rotary wing) with the QL modifier. There will be no rural allowance or mileage billed. View the article for air ambulance suppliers. See CMS Internet Only Manual, 100-2, Medicare Benefits Policy Manual, Chapter 10, Section 10.4.9.
GM When more than one patient is transported in an ambulance and document details of the transport. Used by both ground and air transports. See CMS Internet Only Manual, 100-4, Chapter 15, Section 30.1.2
GA The provider or supplier has provided an Advance Beneficiary Notice (ABN) to the patient.
GZ The provider or supplier expects a medical necessity denial; however, did not provide an Advance Beneficiary Notice (ABN) to the patient.

There are only four situations where the Limitation of Liability provision applies to ambulance suppliers. In those situations a CMS approved Advance Beneficiary Notice form is needed by an ambulance company to reverse the limitation of liability.


Modifier fact sheet for GA modifier

Modifier fact sheet for GZ modifier