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N64 Remark Code: From and To Dates Must Differ

N64 means the 'from' and 'to' dates on the claim or line must be different. The payer expects this service or claim to cover a span of time, but the start and end dates submitted are the same.

Quick facts

Code
N64 (RARC N64)
Status
Active In use since January 1, 2000.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim is denied as a correctable date error. It is not the patient's responsibility.
  • OA (Other Adjustment): Some payers report it as another adjustment because the claim could not be processed with those dates.
Official description
The 'from' and 'to' dates must be different.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N64 means

Some services are, by definition, delivered over a period rather than on a single day. For those, payers expect the claim to show a real date range. When the from and to dates are identical, the payer’s edits treat the claim as internally inconsistent and return N64.

N64 is almost always paired with CARC 16. The fix is usually a date correction, but sometimes the underlying issue is a coding or bill type choice.

Common causes

  • A monthly or periodic service was billed with only the date of the first contact.
  • An equipment rental period was reported as a single date.
  • Charge entry copied the from date into the to date by default.
  • A service billed per period was coded when the actual service was per day.
  • The statement covers period on an institutional claim was entered incorrectly.

How to fix it

  1. Determine the correct period. Check the service record for when the period began and ended.
  2. Confirm the code or bill type matches a period-based service; if the service was a one-day service, change the code instead.
  3. Correct the dates in box 24A (from and to) on the CMS-1500 or the statement period on the UB-04.
  4. Submit a corrected claim with resubmission code 7, or the institutional replacement process.

How to prevent it

Set charge entry defaults for period-based services so they require an end date, and add a pre-bill edit that flags matching from and to dates on codes that need a span. Review monthly billing batches for this pattern before release.

Codes that may appear with N64

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): A billing error, specifically in the service dates.
  • N62 (Dates of service span multiple rate periods.): Dates of service span multiple rate periods and need separate claims.
  • N74 (Resubmit with multiple claims, each claim covering services provided in only one calendar month.): Each claim should cover only one calendar month.
  • N300 (Missing/incomplete/invalid occurrence span date(s).): Occurrence span dates are missing or invalid.
  • CO-110 (Billing date predates service date.): The billing date predates the service date, another date sequencing problem.

N64 FAQ

Which services require different from and to dates?

It depends on the payer. Typical examples include monthly or periodic services, equipment rentals billed for a rental period, and some institutional stays where the payer expects a span. Check the payer's billing guide.

What if the service really occurred on one day?

Then the service may have been coded with a code or bill type meant for a period. Confirm that the code and bill type match what was provided.

Do inpatient claims need different dates?

Inpatient admissions usually span at least one night, so the dates differ. Same-day admit and discharge situations have special rules, so verify how the payer expects them to be billed.