EOB denial code CO-252: what it means

What it means

The insurer needs additional documentation (such as medical records) before it can decide the claim. A remark code usually says exactly what.

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

Official X12 description

“An attachment/other documentation is required to adjudicate this claim/service”

Typical cause

Required supporting documentation was not submitted with the claim.

What to do next

1. 1Look for the remark code next to CO-252 to see what document is needed.
2. 2Ask your provider's billing office to send the requested documentation and resubmit.