CO-286 denial code
Appeal time limits not met
How to fix it
Check whether a further level remains available. Otherwise the determination is final.
How to prevent it
Appeal deadlines are shorter than filing deadlines and start at the denial date. Track them separately.
The CO prefix marks this a contractual obligation. The balance is absorbed by the provider under the payer agreement and cannot be transferred to the patient.
In practice
A denial arrives in March. The claim sits in a work queue and the appeal is submitted in July. The plan returns CO-286 because the appeal deadline was sixty days.
The appeal window runs from the denial date and is much shorter than the filing window. A claim filed well within time can still lose its appeal rights entirely.
Check whether a further level remains, because a late first-level appeal does not always end the process. Where nothing remains, a payable claim has been lost to a calendar rather than to a determination.
What sits behind it
The two deadlines are structurally different and confusing them is the underlying error. Filing runs from the date of service and is frequently a year or more. Appeal runs from the remittance date and is frequently sixty or ninety days.
Denial ageing is the practical control. Working denials by appeal deadline proximity rather than by balance or by date received keeps the shortest-fused items at the front, which is the opposite of how most queues naturally order themselves.
Because these losses are procedural, they are invisible in the usual denial metrics. A practice measuring denial rate and overturn rate can be losing steadily to expired appeal windows without either number showing it.
Related codes
Terms used here — Appeal · Timely Filing · Days in AR
How we handle it — Denial Management · AR Management · Practice Analytics
Primary sources
The rules behind CO-286, at the bodies that publish them.
- Medicare timely filing requirements (opens in a new tab)
Centers for Medicare & Medicaid Services — The one-year filing limit and the narrow exceptions to it. Commercial payers set their own, usually shorter, limits by contract.
- Medicare claims appeals process (opens in a new tab)
Centers for Medicare & Medicaid Services — The five levels of appeal, what each requires and the deadline for each. Missing a level's deadline ends the appeal regardless of the claim's merits.
- Medicare Claims Processing Manual (opens in a new tab)
Centers for Medicare & Medicaid Services — The operative manual for how Medicare claims must be coded, submitted, adjusted and appealed. When a payer policy and a vendor's advice disagree, this settles it.
Looking for a different code? Search all 190 CARC and RARC codes
Questions about CO-286
Commonly sixty to ninety days from the remittance date, though it varies by payer and product. That is much shorter than the filing window, which runs from the date of service and is frequently a year or more.
By appeal deadline proximity rather than by balance or by date received. That is the opposite of how most queues naturally order themselves, which is exactly why appeal windows expire on claims that were otherwise perfectly payable.
Usually not. Denial rate and overturn rate do not capture claims that were never appealed, so a practice can be losing steadily to expired windows while both numbers look acceptable. Tracking appeals filed against appeals available is what surfaces it.
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