Quick answer: Ambulance medical billing is the process of turning an ambulance transport into payment from Medicare, Medicaid, commercial insurers or the patient. It covers coding the transport from the patient care report, checking coverage, submitting the claim with the right level-of-service code, mileage and origin and destination modifier, then posting payment, working denials and billing any balance the patient owes.
Ambulance medical billing looks like other medical billing from a distance: a service is provided, a claim goes to a payer, money comes back. Up close it follows its own rules. Ambulance claims are priced by the level of care given in the vehicle and the miles traveled with the patient on board, payment depends on the ZIP code where the patient was picked up, and Medicare covers the trip only when other transport would have endangered the patient.
The 8 steps from patient care report to payment
- Documentation. The crew completes the electronic patient care report (ePCR): the patient’s condition, care given, pickup and drop-off locations, and loaded mileage.
- Intake and eligibility. The billing team collects demographics and insurance, often from the receiving hospital’s face sheet, and checks coverage electronically.
- Medical necessity review. The documentation is checked to confirm the patient needed an ambulance and the level of care billed. Non-emergency trips may need a physician certification statement (PCS).
- Coding. The coder assigns the HCPCS level-of-service code, the mileage code with loaded miles, and an origin and destination modifier on each line.
- Claim scrubbing and submission. The claim is checked against the payer’s rules, then submitted electronically.
- Payment posting. Payments and remittance advice are posted, and amounts are compared with what the payer should have paid.
- Denials and appeals. Denied claims are traced to a cause, corrected or appealed within the payer’s deadline.
- Patient billing and follow-up. Deductibles, coinsurance and self-pay balances are billed to the patient, and unpaid claims are followed up until they are paid or closed.
When these steps are run as one process with monthly reporting, the result is ambulance revenue cycle management.
The codes used in ambulance billing
Ambulance claims use HCPCS Level II codes, not the CPT office-visit codes used in physician billing. Each transport is billed with a base rate code for the level of service and a separate mileage code.
| HCPCS code | Description |
|---|---|
| A0428 | Basic Life Support (BLS), non-emergency transport |
| A0429 | BLS, emergency transport |
| A0426 | Advanced Life Support (ALS), non-emergency transport, Level 1 |
| A0427 | ALS, emergency transport, Level 1 |
| A0433 | ALS, Level 2 (ALS2) |
| A0434 | Specialty care transport (SCT) |
| A0432 | Paramedic intercept, rural area volunteer ambulance |
| A0430 | Air ambulance, fixed wing, one way |
| A0431 | Air ambulance, rotary wing, one way |
| A0425 | Ground mileage, BLS or ALS, per statute mile |
| A0435 | Air mileage, fixed wing, per statute mile |
| A0436 | Air mileage, rotary wing, per statute mile |
Source: Noridian Medicare hospital-based ambulance billing guide. Our ambulance billing codes guide explains the criteria that separate each level.
Mileage
Only loaded miles are billed: the miles traveled with the patient on board. Medicare requires mileage in fractional units. Under 100 miles, round up to the nearest tenth of a mile (for example 0.9 or 12.4); at 100 miles or more, round up to the nearest whole mile (Noridian).
Origin and destination modifiers
Every ambulance code line carries a two-letter modifier: the first letter is where the trip started, the second where it ended. RH means residence to hospital, SH means scene of an accident or acute event to hospital, and HH means hospital to hospital. A missing or mismatched modifier is a common reason claims are rejected. See the full list in our guide to ambulance origin and destination modifiers.
Medical necessity: when Medicare pays for an ambulance
Medicare covers an ambulance transport only when other means of transportation are contraindicated, meaning they would endanger the patient, and only for the level of service the patient’s condition required (42 CFR 410.40).
For non-emergency trips, being bed-confined is one factor in that decision, not the only test. A patient counts as bed-confined only if all three apply: they cannot get up from bed without help, cannot walk, and cannot sit in a chair or wheelchair. A patient who is not bed-confined can still qualify if their condition requires ambulance transport.
Medicare also limits covered destinations. The main ones are trips from any point of origin to the nearest hospital, critical access hospital, rural emergency hospital or skilled nursing facility that can provide the care needed; from one of those facilities to the patient’s home; and for dialysis patients with end-stage renal disease, between home and the nearest dialysis facility.
Physician certification statements (PCS)
Many non-emergency transports need a PCS, a signed statement that the trip was medically necessary:
| Type of non-emergency trip | PCS rule |
|---|---|
| Repetitive, scheduled (for example, dialysis three times a week) | PCS obtained before the trip, dated no earlier than 60 days before the service |
| Non-repetitive scheduled, or unscheduled, for a patient in a facility under a physician’s care | PCS obtained within 48 hours after the trip |
| Attending physician unavailable | A certification may be signed by staff with knowledge of the patient, such as a physician assistant, nurse practitioner, registered nurse, case manager or discharge planner |
| Certification not returned within 21 calendar days | The supplier documents its attempts, for example with a signed postal return receipt, and may then submit the claim |
A signed PCS does not prove medical necessity on its own; the patient care report must support it (42 CFR 410.40). Our Medicare ambulance billing guide covers these rules in more depth.
Who pays for an ambulance ride
| Payer | How billing works |
|---|---|
| Medicare Part B | Paid under the Ambulance Fee Schedule, adjusted by the ZIP code where the patient was picked up. Providers must accept the Medicare allowed amount and bill the patient only the Part B deductible and coinsurance (CMS) |
| Medicaid | State rules, often through managed care plans; see our Medicaid ambulance billing guide |
| Commercial insurance | Plan contracts and policies; out-of-network rules vary by state |
| Patient | Deductibles, coinsurance and self-pay balances |
Medicare also requires claims to be filed within 1 calendar year after the date of service (42 CFR 424.44).
Where ambulance claims get denied
Most denials trace back to a handful of causes:
- Documentation that does not support medical necessity or the level of service billed
- Missing or late PCS forms for non-emergency trips
- Missing, reversed or mismatched origin and destination modifiers
- Mileage that is missing, not loaded, or not reported in fractional units
- Wrong or lapsed insurance, or the wrong payer order for patients with two plans
- Missing patient or facility signatures
- Claims filed after the payer’s deadline
Our guide to the top 7 ambulance billing denials explains how to prevent each one.
Handling ambulance billing in house or with a partner
Some agencies bill with their own staff; others hire a specialist. Either way, the steps and rules above are the same, and they differ from physician and hospital billing in 9 ways that affect payment. If you are weighing the options, our in-house vs outsourced ambulance billing comparison walks through the costs. AmbulanceMedicalBilling.com provides ambulance billing services for ground, air and NEMT transports, and a free billing audit shows where your current claims are losing revenue.
Frequently asked questions
What is ambulance medical billing?
It is the process of billing Medicare, Medicaid, commercial insurers and patients for ambulance transports. It includes coding each trip from the patient care report, verifying coverage, submitting claims, posting payments, working denials and billing patient balances.
Who bills for an ambulance ride?
The ambulance provider bills, either through its own billing staff or a billing company acting on its behalf. Hospitals bill separately for care given after arrival.
What codes are used for ambulance billing?
HCPCS Level II codes: a base rate code for the level of service, such as A0429 for a BLS emergency transport or A0427 for ALS1 emergency, plus a mileage code such as A0425 for ground miles. Each line also carries an origin and destination modifier.
Does Medicare cover ambulance transport?
Medicare Part B covers ambulance transport when other means of transportation would endanger the patient’s health, for the level of service the condition requires, and to covered destinations such as the nearest appropriate hospital.
How long does an ambulance provider have to file a Medicare claim?
Medicare generally requires claims to be filed within 1 calendar year after the date of service. Medicaid and commercial deadlines vary by state and plan, so check each payer’s manual.
Do all non-emergency ambulance trips need a PCS?
Not all. Repetitive scheduled trips need a PCS dated within 60 days before the service, and other non-emergency trips for facility patients under a physician’s care need one within 48 hours after the trip. Patients at home not under a physician’s direct care do not need one.