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N53 Remark Code: Invalid Ambulance Pick-Up Address

N53 means the point of pick-up address on the claim was missing, incomplete, or invalid. Ambulance claims must report where the patient was picked up, because payers use that location, especially the ZIP code, to price the trip and check coverage.

Quick facts

Code
N53 (RARC N53)
Status
Active In use since January 1, 2000; last modified February 28, 2003.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim is denied as a correctable billing error. It is not the patient's responsibility.
  • PI (Payer Initiated Reduction): Some government payers report it as a payer-initiated adjustment for the same error.
Official description
Missing/incomplete/invalid point of pick-up address.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N53 means

Ambulance payment depends heavily on where the trip began. Payers use the pick-up location to determine the fee schedule locality, apply rural or urban adjustments, and confirm the trip met coverage rules for origin and destination. N53 says the pick-up address on the claim could not be used: it was blank, lacked required parts such as the ZIP code, or was not a valid address.

N53 is typically paired with CARC 16. Correcting the location usually resolves it.

Common causes

  • The electronic ambulance claim left out the pick-up location, or included only a partial address.
  • The ZIP code was missing, mistyped, or did not match the city and state.
  • The base station address was reported instead of the actual pick-up location.
  • For scene responses, the crew’s run report used a description the billing system did not carry over.
  • On paper claims, the pick-up ZIP was placed in the wrong box.

How to fix it

  1. Review the patient care report to confirm where the patient was picked up.
  2. Validate the address and ZIP code, using a postal lookup if needed.
  3. Enter it in the ambulance pick-up location on the 837P, or in the payer-specified field on a CMS-1500.
  4. Confirm the drop-off location is also complete to avoid a follow-up denial.
  5. Submit a corrected claim with resubmission code 7 and the original claim number.

How to prevent it

Have ePCR software require a validated pick-up address and ZIP for every transport, and map it directly into the claim. Add a pre-bill edit that blocks ambulance claims missing pick-up or drop-off ZIP codes.

Codes that may appear with N53

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim is missing information; N53 identifies the pick-up location.
  • N756 (Missing/incomplete/invalid point of drop-off address.): The point of drop-off address is missing or invalid.
  • N157 (Transportation to/from this destination is not covered.): Transportation to or from this destination is not covered.
  • 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.

N53 FAQ

Why does the pick-up ZIP code matter?

For Medicare and many other payers, the pick-up ZIP code determines the payment locality and whether rural adjustments apply. Without it, the trip cannot be priced.

Where does the pick-up information go on a paper claim?

Medicare instructions have long called for the pick-up ZIP code in box 23 of the CMS-1500 for ambulance claims. Other payers may have different instructions, so check their billing guide.

What if the pick-up location has no street address?

For scenes such as highways or rural locations, use the most precise description and ZIP code available, following payer guidance. Many payers accept a descriptive location with an accurate ZIP code.