Skip to main content

N811 Remark Code: Prior Payer Sequestration Missing

N811 means the secondary claim did not report the federal sequestration reduction taken by the prior payer, usually Medicare. The secondary payer needs that adjustment, normally reported as CARC 253, to calculate what it owes.

Quick facts

Code
N811 (RARC N811)
Status
Active In use since November 1, 2018.
Code set
Remittance Advice Remark Codes (RARC)
Group codes
  • CO (Contractual Obligation): The claim was denied or held for incomplete prior-payer data. The provider corrects it; the patient is not billed for this reason.
Official description
Missing Federal Sequestration Reduction from Prior Payer.
X12 Remittance Advice Remark Codes, retrieved September 25, 2026
Last verified
against the official X12 list.

What N811 means

When Medicare pays a claim, it applies a small federal sequestration reduction to the payment and reports it on the remittance, normally as CO-253. If a secondary payer then receives the claim, it expects to see every adjustment the primary made, including that one. N811 means the sequestration line was missing from the prior-payer information on your secondary claim.

This is a coordination of benefits (COB) data issue. The secondary payer typically returns N811 with CARC 16 and won’t process the claim until the prior-payer adjustments are complete.

Common causes

  • Manual COB entry. Staff keyed in the primary paid amount and patient responsibility but skipped the sequestration line.
  • Posting rules that write off CO-253 silently without storing it as a reportable adjustment.
  • Paper secondary claims sent with a summary of the primary payment instead of the full remittance detail.
  • Crossover gaps. A claim didn’t cross over automatically, and the manually billed secondary lacked the full adjustment detail.

How to fix it

  1. Open the primary remittance for the date of service and find the CARC 253 amount on each line.
  2. Add it to the prior-payer adjustments on the secondary claim, at the same level and with the same group code (usually CO) that the primary used.
  3. Check that the claim balances: billed charge equals primary paid plus all primary adjustments.
  4. Submit a corrected claim with resubmission code 7 in box 22 or its electronic equivalent. For paper, attach the primary remittance showing the reduction.

How to prevent it

  • Let your billing system build secondary claims directly from the posted primary remittance rather than retyping amounts.
  • Make sure CO-253 posts as its own adjustment, not merged into CO-45.
  • Run secondary claims through Claims Validator to catch prior-payer data that doesn’t balance. See also eligibility and COB denials.

Codes that may appear with N811

  • CO-16 (Claim/service lacks information or has submission/billing error(s).): The claim lacks information for adjudication; N811 names the missing sequestration adjustment.
  • CO-129 (Prior processing information appears incorrect.): Prior processing information appears incorrect or incomplete.
  • CO-253 (Sequestration - reduction in federal payment): The primary payer's sequestration adjustment that must be carried to the secondary claim.
  • N4 (Missing/Incomplete/Invalid prior Insurance Carrier(s)): The prior payer's EOB or remittance as a whole is missing or invalid.
  • OA-23 (The impact of prior payer(s) adjudication including payments and/or adjustments. (Use only with Group Code OA)): How the secondary payer reports the effect of the prior payer's payments and adjustments.

N811 FAQ

What is the sequestration reduction?

It is an across-the-board reduction to certain federal payments, including Medicare fee-for-service claim payments, required by federal budget law. Medicare reports it on the remittance with CARC 253.

Why does the secondary payer care about it?

Without it, the primary's paid amount and adjustments don't add up to the billed charge, so the secondary can't balance the claim or tell who is responsible for that amount.

Do I report sequestration as patient responsibility?

No. Report it exactly as the primary payer did, typically as a CO adjustment with CARC 253.