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N325 Remark Code: Last Worked Date Missing

N325 means the last date the patient worked was missing, incomplete, or invalid. Workers' compensation and disability-related payers use it to establish when the patient stopped working because of the injury or condition.

Quick facts

Code
N325 (RARC N325)
Status
Active In use since December 2, 2004.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The provider must supply a valid date; the adjustment is not billed to the patient.
Official description
Missing/incomplete/invalid last worked date.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N325 means

The last worked date is a small but important detail in work-injury and disability claims. It helps a carrier connect treatment to the time the patient stopped working and calculate related benefits. N325 means the carrier needed that date and couldn’t use what was on the claim, often because nothing was sent.

It generally comes with CARC 16.

Common causes

  • Intake didn’t ask when the patient last worked.
  • The injury date was used instead, even though the patient kept working afterward.
  • The last worked date is after the disability start date or after the date of service.
  • The patient returned to work and stopped again, and the claim didn’t reflect the most recent stop.
  • The carrier requires the date on its own form, which wasn’t submitted.

How to fix it

  1. Confirm the last day the patient actually worked, with the patient, employer, or claim adjuster.
  2. Check that it fits logically with the injury date and disability period.
  3. Enter it in the field or form the carrier requires.
  4. Resubmit using the carrier’s correction process, often frequency code 7.

How to prevent it

Workers’ compensation intake should always capture the injury date, the last worked date, and the employer’s contact, alongside the carrier’s claim number. Keep those details in structured fields tied to the case, not the individual visit, so every claim in the case uses them consistently. When the patient’s work status changes, update the case record promptly. Our COB and eligibility guide covers how to route claims when both a health plan and a work-injury carrier are involved.

Codes that may appear with N325

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): Missing or invalid information; N325 names the last worked date.
  • OA-19 (This is a work-related injury/illness and thus the liability of the Worker's Compensation Carrier.): The condition was determined to be work-related and the liability of workers' compensation.
  • N315 (Missing/incomplete/invalid disability from date.): The disability 'from' date is missing or invalid.
  • N311 (Missing/incomplete/invalid authorized to return to work date.): The authorized return-to-work date is missing or invalid.
  • N305 (Missing/incomplete/invalid injury/accident date.): The injury or accident date is missing or invalid.

N325 FAQ

How is the last worked date different from the disability start date?

The last worked date is the final day the patient actually worked. The disability start date is when they became unable to work. They are often a day apart but can differ.

Who provides the last worked date?

Usually the patient or employer. The clinician records it, and billing reports it.

Where does it go on the claim?

Many workers' compensation carriers specify their own fields or state forms. On the CMS-1500, box 16 captures the period the patient couldn't work. Follow the carrier's instructions.