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N345 Remark Code: Date Range Not Valid with Units

N345 means the from-to date range on a service line is not consistent with the number of units billed. For example, a line billed with more per-day units than the date span allows, or a one-day line with units that imply several days.

Quick facts

Code
N345 (RARC N345)
Status
Active In use since March 30, 2005.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The line was denied for a billing inconsistency the provider can correct. The patient is not responsible for this amount.
Official description
Date range not valid with units submitted.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N345 means

Each service line carries a from date, a to date, and a unit count. Payers run edits to check that the three agree. N345 is returned when they don’t: the unit count is impossible for the span of days reported, or the span is wider or narrower than the units suggest.

It usually explains CARC 16 because the claim has an internal billing error. The payer has not judged medical necessity yet; it just can’t process the line as submitted.

Typical examples

  • A per-day item billed from the 1st to the 3rd with 10 units, when the item is limited to one unit per day.
  • A line with the same from and to date but units that represent a whole month of supply.
  • A span entered backwards, with the to date earlier than the from date.
  • Rentals billed with a date span that doesn’t match the monthly unit.

How to fix it

  1. Look at the source. Compare the line to the medical record, delivery log, or visit notes to see what actually happened on which days.
  2. Decide whether to split. If the payer wants one line per date, break the span into separate lines with the units for each day.
  3. Check unit definitions. Confirm what one unit means for the code billed (per day, per item, per 15 minutes). Our MUE and units guide explains how payers limit units.
  4. Correct dates or units in box 24A and 24G on the CMS-1500 (or the matching 837P service line fields).
  5. Resubmit as a corrected claim with resubmission code 7 and the original claim number.

How to prevent it

Set up charge entry rules that flag lines where units exceed the day count times the code’s daily maximum, or where a span is used for a code your payers require by date. A tool such as Claims Validator can catch these conflicts before submission.

Codes that may appear with N345

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim has a billing error; N345 identifies the conflict between dates and units.
  • CO-151 (Payment adjusted because the payer deems the information submitted does not support this many/frequency of services.): The payer deems the information does not support this many services, which can apply once units are reviewed.
  • M53 (Missing/incomplete/invalid days or units of service.): Used when the days or units of service are missing or invalid on their own.
  • N362 (The number of Days or Units of Service exceeds our acceptable maximum.): Indicates the days or units exceed the payer's acceptable maximum.
  • N430 (Procedure code is inconsistent with the units billed.): Says the procedure code is inconsistent with the units billed.

N345 FAQ

Can I bill several days on one line?

Some payers accept a date span on one line for certain services, such as daily supplies or rentals. Others require one line per date. Check the payer's rules for the specific service.

What if the units are correct and the dates are wrong?

Then correct the dates. N345 only tells you the two don't agree; you decide which one is wrong based on the record.

Does N345 apply to time-based services?

It can. If time units are billed across a date span, the payer may check that the total is plausible for the number of days.