EOB denial code · CO group
CO-22: Coordination of Benefits — Who Pays First?
CO-22 tells you the insurer believes another health plan should pay this claim first — coordination of benefits (COB). If you have two plans (e.g., through your employer and a spouse's), the claim needs to be billed to the correct primary first. CO-22 is a paperwork ordering problem, not a service you owe for.
What “CO-22” means on your EOB
This care may be covered by another payer per coordination of benefits.
Who pays? CO — Contractual Obligation
CO (contractual) — the amount is being held until the correct primary payer processes the claim. You don't owe it; the claim ordering needs fixing.
What to do next: Give the provider your other plan's ID card and ask them to submit to the correct primary first. Once the primary responds, the secondary insurer processes the remainder. If the secondary plan still shows CO-22 after the primary has paid, call the secondary's COB department — they may not have the primary's EOB on file.
Why this denial happens
- You have two active insurance plans and the claim was billed to the wrong one first.
- The provider only had one insurance card on file.
- Your policy status (active/inactive) wasn't updated at the time of service.
- The payer's COB records show a different plan as primary than the one you think is primary.
What to do now
- Call the primary plan (per your coordination-of-benefits rules — usually the plan covering you as the employee, or birthday-rule for dependents) and verify the claim was filed there.
- Give your provider both insurance ID cards so they can submit in the right order.
- If both plans already processed it, confirm the secondary has the primary's EOB.
- If you only have ONE plan, call the insurer's COB line — an outdated COB record (e.g., an old employer plan) is the likely cause and they can correct it.
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Generate an appeal letter →I only have one insurance plan — why do I see CO-22?
The payer's records may still list an old plan (previous employer, parent's plan) as primary. Call the COB department and ask them to remove the outdated policy so the claim reprocesses.
Which plan pays first with two insurances?
The 'employee birthday rule' usually applies for dependents, and the plan covering you as the primary employee pays first for you. Your plan documents state the order; the provider needs both cards either way.
Do I owe the CO-22 amount?
No. It's a hold while the payer waits for the correct primary to process. Fix the ordering and the claim will be re-adjudicated.