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N158 Remark Code: Non-Ambulance Vehicle Not Covered

N158 means transportation in a vehicle other than an ambulance is not covered. The payer's benefit applies only to ambulance transport, and the claim indicated, or the payer determined, that another type of vehicle was used.

Quick facts

Code
N158 (RARC N158)
Status
Active In use since February 28, 2003.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The transport provider carries the amount unless the patient accepted liability in advance.
  • PR (Patient Responsibility): The patient may be responsible if the plan excludes the service and the patient agreed to pay.
Official description
Transportation in a vehicle other than an ambulance is not covered.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N158 means

The ambulance benefit covers transport in a vehicle designed, equipped, and staffed as an ambulance when the patient’s condition requires it. N158 tells you the trip was in some other vehicle, so it falls outside that benefit.

It usually pairs with CARC 96. N158 does not address medical necessity; it addresses the vehicle.

Common causes

  • A wheelchair or stretcher van service billed under ambulance codes or to a payer without a non-emergency transport benefit.
  • A provider enrolled for non-emergency transport billed a plan whose benefit covers ambulances only.
  • The HCPCS code on the claim described a non-ambulance service.
  • The payer’s enrollment file shows the provider as a non-ambulance vendor.

What to do

  1. Confirm the vehicle and service level from the trip record.
  2. Check the patient’s benefits for non-emergency medical transportation, which may be billed differently or arranged through a broker.
  3. If an ambulance was used, correct the codes or enrollment data and resubmit.
  4. If not, the ambulance benefit does not apply. Bill the correct benefit if one exists, or resolve the balance per the group code.

How to prevent it

Verify which transport benefit applies before scheduling non-emergency trips, and bill each vehicle type to the right benefit. Keep enrollment current for every service type you offer.

Codes that may appear with N158

  • CO-96 (Non-covered charge(s).): A non-covered charge; N158 names the vehicle type as the reason.
  • PR-204 (This service/equipment/drug is not covered under the patient's current benefit plan): The service is not covered under the patient's current benefit plan.
  • N157 (Transportation to/from this destination is not covered.): Transport to or from the destination is not covered.
  • N904 (The transportation vendor is responsible for this claim.): The transportation vendor is responsible for the claim.
  • N159 (Payment denied/reduced because mileage is not covered when the patient is not in the ambulance.): Mileage is not covered when the patient is not in the ambulance.

N158 FAQ

What vehicles trigger N158?

Wheelchair vans, stretcher vans, taxis, and other non-emergency vehicles that are not equipped and staffed as ambulances.

Is non-ambulance transport ever covered?

Some payers, especially Medicaid programs, cover non-emergency medical transportation under a separate benefit, often through a broker. Billing it under the ambulance benefit leads to N158.

What if an ambulance was used?

Check that the claim used ambulance codes and that the payer has your ambulance enrollment on file. Correct the claim or enrollment and resubmit.