EOB denial code CO-29: what it means

What it means

The claim was submitted after the insurer's filing deadline, so it was not paid.

Contractual Obligation — an adjustment the provider agreed to by contract. The patient is generally not billed for CO amounts.

Official X12 description

“The time limit for filing has expired”

Typical cause

The provider sent the claim too late, past the plan's timely-filing window.

What to do next

1. 1This is almost always a provider responsibility — you should not be billed for a late-filing denial.
2. 2Ask your provider's billing office why the claim was filed late and to appeal if there was good cause.