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N303 Remark Code: Principal Procedure Date Invalid

N303 means the date of the principal procedure was missing, incomplete, or invalid. On an inpatient claim, the principal procedure code must be reported with the date it was performed, and the payer couldn't accept the date given.

Quick facts

Code
N303 (RARC N303)
Status
Active In use since December 2, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): A correctable institutional claim error. The facility fixes the date and resubmits; the patient is not billed.
Official description
Missing/incomplete/invalid principal procedure date.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N303 means

The principal procedure is the most significant procedure performed during an inpatient stay, reported with an ICD-10-PCS code in UB-04 form locator 74 along with its date. Payers use the code and date to group the stay, check authorization windows, and confirm the procedure happened during the admission. N303 says the date part was the problem.

You will usually see it with CARC 16.

Common causes

  • The abstract was finalized with a principal procedure code but no date.
  • The date entered is outside the admission-to-discharge range.
  • The date reflects when the procedure was scheduled or documented rather than performed.
  • The principal procedure was re-sequenced during coding review, and the old date stayed attached to the new code.
  • The date was entered in the wrong format for the claim system.

Correcting the claim

  1. Open the operative report or procedure note for the principal procedure and confirm the performance date.
  2. Confirm the date falls between admission and discharge.
  3. If the principal procedure was re-sequenced, check that every procedure code still sits beside its own date.
  4. Update form locator 74 or the 837I principal procedure date.
  5. Submit a replacement claim with frequency code 7 and the original claim number.

If the stay required prior authorization, make sure the corrected date still falls within the approved window. The authorization denials guide covers date-window problems in more depth.

How to prevent it

Require a date on every procedure code in the coding abstract, and compare procedure dates to admission and discharge dates automatically before the claim is released. When coding review re-sequences procedures, recheck dates as part of the same step.

Codes that may appear with N303

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Missing or invalid information; N303 names the principal procedure date.
  • CO-A8 (Ungroupable DRG.): An ungroupable DRG may appear when principal procedure data can't be processed.
  • MA66 (Missing/incomplete/invalid principal procedure code.): The principal procedure code itself is missing or invalid.
  • N302 (Missing/incomplete/invalid other procedure date(s).): An other procedure's date is the problem.
  • N301 (Missing/incomplete/invalid procedure date(s).): The general remark for procedure dates.

N303 FAQ

Where is the principal procedure date reported?

UB-04 form locator 74, next to the principal procedure code. The 837I reports it with the principal procedure information.

What is the principal procedure?

Generally the procedure performed for definitive treatment rather than for diagnostic or exploratory purposes, or the one most closely related to the principal diagnosis.

Does N303 mean the procedure isn't covered?

No. N303 is about the date. Coverage is decided after the payer can process the corrected claim.