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N401 Remark Code: Missing Periodontal Charting

N401 means the dental payer required periodontal charting, typically pocket depth measurements and related findings, to process the claim, and the charting was not received.

Quick facts

Code
N401 (RARC N401)
Status
Active In use since August 1, 2007.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim is denied until the periodontal charting is received. The dental office supplies it; the patient is not billed while it's outstanding.
Official description
Missing periodontal charting.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N401 means

Dental plans rely on periodontal charting to decide whether periodontal treatment is justified. The chart records pocket depths and related findings for each tooth, which show the extent of disease. N401 says the plan needed that chart for this claim and didn’t get it.

N401 generally sits with CARC 252 or CARC 163.

Common causes

  • The claim was sent without attachments, even though the plan requires charting for the procedure.
  • Only radiographs were attached; the charting was left out.
  • The attachment was sent separately and wasn’t matched to the claim.
  • The chart is stored in imaging or charting software that doesn’t export automatically with claims.

What to do

  1. Pull the full perio chart from the exam that supported the treatment, including the date it was recorded.
  2. Confirm it’s recent enough for the plan’s policy.
  3. Add any other required items, such as radiographs or a narrative describing the diagnosis and treatment plan.
  4. Attach it through the payer’s electronic attachment service or portal, referencing the claim number.
  5. Follow up to confirm the claim was reprocessed.

If the chart can’t be found, don’t create one after treatment to fill the gap. Talk to the treating dentist about what documentation from the diagnostic visit does exist, and ask the plan whether a narrative with radiographs can be reviewed instead.

How to prevent it

For periodontal procedures, set your practice management system to require the perio chart attachment before the claim can be sent. Record a full charting at the diagnostic appointment so it’s available when treatment is billed.

Codes that may appear with N401

  • CO-252 (An attachment/other documentation is required to adjudicate this claim/service.): An attachment is required; N401 identifies the periodontal charting.
  • CO-163 (Attachment/other documentation referenced on the claim was not received.): The attachment referenced on the claim was not received.
  • N402 (Incomplete/invalid periodontal charting.): Used when periodontal charting was received but is incomplete or invalid.
  • N682 (Missing/Incomplete/Invalid history of prior periodontal therapy/maintenance.): Covers missing or invalid history of prior periodontal therapy or maintenance.
  • N346 (Missing/incomplete/invalid oral cavity designation code.): Addresses a missing or invalid oral cavity designation code, often needed on quadrant-based perio procedures.

N401 FAQ

Which procedures need perio charting?

Typically periodontal treatments such as scaling and root planing or periodontal surgery. Each plan sets its own documentation rules.

How recent must the charting be?

Plans often expect charting taken within a limited period before treatment. Check the plan's requirement.

Should I send radiographs too?

Many plans want recent radiographs along with the charting for periodontal procedures. Follow the payer's attachment list.