Coordination of Benefits Denials

CARC 22

The claim should be paid by another insurance first, or the wrong plan was billed.

What it is

The pattern

A coordination-of-benefits denial says the claim belongs to another payer first — another insurance plan, another coverage period, or the wrong plan entirely. The payer is telling you the primary/secondary order is wrong, not that the service failed.

Why it happens

Common causes

The patient had other coverage that was never identified.
The primary plan was billed but the patient's coverage was actually secondary.
The claim went to the wrong plan (e.g., commercial instead of the plan covering the DOS).
A prior injury/work comp/auto lien was the true primary.

Prevention

Stop it before the claim goes out

Collect full insurance information at intake — every plan, not just the one the patient volunteers.
Run eligibility and check for other coverage indicators before rendering.
Identify liens (work comp, auto, other insurance) during scheduling for accident-related visits.

When it happens

What to do

Confirm the correct primary, bill it, and let the secondary pay the remainder — or if the wrong plan was billed, have the claim forwarded to the correct plan within the payer's window. If the payer applied the wrong COB order, appeal with the coverage evidence showing the correct primary.

Deeper dive

The full denial guide

Another plan may be primary, the primary's payment was not applied correctly, or the claim belongs with a different payer under COB rules.

Open the Coordination of Benefits guide →