My claim was denied for coordination of benefits. Who pays first?
A coordination-of-benefits denial means the plan believes another insurer is primary, so it will not pay until that plan processes first or until you update COB information. Fix the order-of-benefits issue, get both plans' EOBs, and appeal if the plan applies the wrong primary/secondary rule.
What to do, in order
- Step 1
Update COB with both plans
Call or portal-message each plan with the other plan's name, member ID, policyholder, effective date, and whether coverage is active or ended.
- Step 2
Get the primary plan's EOB
The secondary plan usually needs proof of what the primary plan paid or denied before it will process.
- Step 3
Check the order rule
Common rules include active employee before retiree, birthday rule for dependent children, custody rules, Medicare rules, and workers' compensation or auto coverage when applicable.
- Step 4
Appeal the wrong order
If the plan insists another plan is primary, ask for the rule it used and send documents proving the correct order.
The deadline that applies
COB updates should be made immediately because claims can stall. If the plan issues a denial, use the appeal deadline on the letter or EOB, generally at least 180 days on employer and ACA plans.
Calculate your date →Documents to gather
- Both insurance cards
- Both plans' effective dates
- Primary plan EOB or denial
- Divorce/custody order, Medicare letter, or termination letter if relevant
Go deeper
Related questions
Is COB a medical-necessity denial?
No. It is an order-of-payment issue. Fixing COB can get the claim processed without a clinical appeal.
What if the primary plan denied too?
Send that EOB to the secondary plan. The secondary plan still has to process according to its rules.
Can both plans say the other is primary?
Yes, and that is when you ask each plan for the written rule it applied and appeal the plan applying the wrong one.
Sources
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