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N797 Remark Code: Missing or Invalid Date Qualifier

N797 means a date on the claim was sent without a valid date qualifier, the short code that tells the payer what the date represents, such as onset of illness, accident, or last menstrual period. Without it the payer can't interpret the date.

Code: N797 (RARC N797)
Status: Active In use since November 1, 2017.
Code set: Remittance Advice Remark Codes (RARC)
Group codes: CO (Contractual Obligation): The claim was rejected or denied for a data error the provider can correct. It is not billable to the patient.
Official description: Missing/incomplete/invalid date qualifier.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified: September 24, 2026 against the official X12 list.

What N797 means

Claims carry many dates besides the date of service: when symptoms began, when an accident happened, when the patient was last seen, when a prescription was written, when a hospitalization started. On both the paper CMS-1500 and the electronic 837, each of these is sent with a qualifier, a short code that labels what the date is.

N797 appears when a date arrived with no qualifier, an incomplete one, or one that isn’t valid for that field. The payer can see a date but can’t tell what it represents, so it can’t apply rules that depend on it, such as accident coverage, therapy timelines, or pregnancy-related benefits. It generally travels with CARC 16.

Common causes

Blank qualifier field on a paper claim beside box 14 or box 15.
Qualifier from the wrong list, for example a code that is valid for one date field placed next to a different field.
Software or clearinghouse mapping that drops or overwrites qualifiers when converting data to the 837 format.
Legacy templates built before a field’s qualifier requirements changed.

How to fix it

Identify which date triggered the edit. The remittance or clearinghouse report may name the field; if not, review every non-service date on the claim.
Confirm what the date actually is from the chart: onset, accident, last seen, and so on.
Enter the correct qualifier for that field using your software’s options or the payer’s companion guide.
Resubmit. If the claim was rejected at the front end, send it again as a new claim. If it was adjudicated and denied, send a corrected claim with resubmission code 7 in box 22. See claim rejection vs. denial for the difference.

How to prevent it

Make the qualifier a required field in registration and charge-entry screens wherever a secondary date is captured.
After software updates, spot-check a few claims at the clearinghouse to be sure qualifiers are still being sent.
Keep the payer’s companion guide handy for fields that accept only certain qualifiers.

Codes that may appear with N797

CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim has a submission or billing error; N797 points to the date qualifier.

N299 (Missing/incomplete/invalid occurrence date(s).): The occurrence date itself is missing or invalid, not the qualifier describing it.
N800 (Only one service date is allowed per claim.): Only one date of service is allowed per claim.
N812 (The start service date through end service date cannot span greater than 18 months.): The claim's service date range is too long.

N797 FAQ

What is a date qualifier?

It's a code sent next to a date that identifies what the date means, for example an onset date, an initial treatment date, or an accident date. The same calendar date can mean very different things for coverage.

Where is the qualifier on a paper CMS-1500?

Several date fields, such as box 14 for the current illness date and box 15 for another date, have a small qualifier field beside them. On electronic claims your software sends the qualifier with the date.

Is N797 usually a software issue?

Often. When a practice management system sends a date without a qualifier, or a clearinghouse maps it incorrectly, every claim with that field can be affected.

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